Climate change and “atmospheric thirst” to increase fire danger and drought in Nevada and California

Climate change and “atmospheric thirst” to increase fire danger and drought in Nevada and California

Climate change and “atmospheric thirst” to increase fire danger and drought in Nevada and California

New study shows impacts of increased levels of evaporative demand as climate grows warmer and drier

Climate change and a “thirsty atmosphere” will bring more extreme wildfire danger and multi-year droughts to Nevada and California by the end of this century, according to new research from the Desert Research Institute (DRI), the Scripps Institution of Oceanography at the University of California, San Diego, and the University of California, Merced.

In a new study published in Earth’s Future, scientists looked at future projections of evaporative demand – a measure of how dry the air is – in California and Nevada through the end of the 21st century. They then examined how changes in evaporative demand would impact the frequency of extreme fire danger and three-year droughts, based on metrics from the Evaporative Demand Drought Index (EDDI) and the Standardized Precipitation Evapotranspiration Index (SPEI).

According to their results, climate change projections show consistent future increases in atmospheric evaporative demand (or the “atmospheric thirst”) over California and Nevada. These changes were largely driven by warmer temperatures, and would likely lead to significant on-the-ground environmental impacts.

 

Maps showing increases in evaporative demand toward end of next century.

Study results show increases of 13 to 18 percent in evaporative demand during all four seasons by the end of the century.

Credit: Dan McEvoy/DRI.

“Higher evaporative demand during summer and autumn—peak fire season in the region—means faster drying of soil moisture and vegetation, and available fuels becoming more flammable, leading to fires that can burn faster and hotter,” explained lead author Dan McEvoy, Ph.D.,  Assistant Research Professor of Climatology at DRI.

“Increased evaporative demand with warming enables fuels to be drier for longer periods,” added coauthor John Abatzoglou, Ph.D., Associate Professor with the University of California, Merced. “This is a recipe for more active fire seasons.”

The research team found that days with extreme fire danger in summer and autumn are expected to increase four to 10 times by the end of the century. Their results also showed that multi-year droughts, similar to that experienced in California and Nevada during 2012-2016, were projected to increase three to 15 times by the end of the century.

“One major takeaway was that we can expect to see a lot more days in the summer and autumn with extreme fire danger related to increased temperature and evaporative demand,” McEvoy said. “Another takeaway was that even in locations where precipitation may not change that much in future, droughts are going to become more severe due to higher evaporative demand.”

Graph showing increase in extreme fire danger days in 2020.

California and Nevada on average experienced a record-setting number of “extreme fire danger” days in 2020, as indicated by the line on the graph above. Extreme fire danger days were calculated using the Evaporative Demand Drought Index (EDDI), with methods described in McEvoy et al. (2020). Data source: http://www.climatologylab.org/gridmet.html.

Credit: Dan McEvoy/DRI.

Study authors say that the cumulative effects of increases in evaporative demand will stress native ecosystems, increase fire danger, negatively impact agriculture where water demands cannot be met, and exacerbate impacts to society during periods of prolonged dryness. Several members of the research team are part of the California-Nevada Applications Program (CNAP), and will use these study results to provide resource managers with a view of possible future scenarios.

“These results provide information to support science-based, long-term planning for fire management agencies, forest management agencies, and water resource managers,” said coauthor Julie Kalansky, Ph.D., Program Manager for CNAP. “We plan to work with partners to help integrate the findings from this paper to support building climate resilience.”

 

Additional Information:

This study was funded by the National Oceanic and Atmospheric Administration (NOAA) California-Nevada Climate Applications Program (CNAP) and the NOAA National Integrated Drought Information System (NIDIS) California-Nevada Drought Early Warning System.

The full text of the paper, “Projected Changes in Reference Evapotranspiration in California and Nevada: Implications for Drought and Wildland Fire Danger,” is available from Earth’s Future: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020EF001736

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

Wildfire smoke more dangerous than other air pollutants for asthma patients

Wildfire smoke more dangerous than other air pollutants for asthma patients

Photo caption: Smoke from wildfires covering the city of Sparks, Nevada. Credit: GChapel, Adobe Images.

 

Reno, Nev. (Sept. 22, 2020) – For people who suffer from asthma, wildfire smoke is more hazardous than other types of air pollution, according to a new study from the Desert Research Institute (DRI), the Renown Institute for Health Innovation (Renown IHI) and the Washoe County Health District (WCHD).

The study, which published last month in the journal Environmental Health, examined associations between airborne particulate matter (PM) from sources such as wildfire, transportation and industry, and medical visits for asthma at Renown Health’s emergency departments and urgent care centers in Reno, Nev. during the six-year period from 2013-2018.

According to their results, on days when wildfire smoke was present, elevated levels of PM2.5 (fine particles of 0-2.5 micrometers in size, about 30 times smaller than a human hair) led to a 6.1 percent increase in medical visits for asthma patients when compared with days of similar pollution levels that came from non-wildfire sources.

“Since we found significantly stronger associations of PM2.5 with asthma visits when wildfire smoke was present, our results suggest that wildfire PM is more hazardous than non-wildfire PM for patients with asthma,” said lead author Daniel Kiser, M.S., Data Scientist with DRI and Renown IHI.

 


Above, a timelapse video from DRI’s Western Regional Climate Center shows an impressive smoke front move into the city of Reno on August 18, 2013. The smoke, which rolls in at approximately 1:05 in the video, was from the American River fire near Sacramento, Calif.


An increase in the harmfulness of PM from wildfires compared to PM from other sources may be attributable to differences in the chemical composition of PM or changes in human behavior, since people are more likely to be outdoors in the summer, when wildfires typically occur. The research team notes that caution should be used when applying these results to other areas of the country, such as the Southeastern United States, since the harmfulness of wildfire smoke may be affected by the type of fuel that is being burned. Other factors, such as the distance that wildfire smoke was carried by the wind and burn temperature, may also play a role in the harmfulness of wildfire smoke.

The researchers found that air quality in the Reno area was affected by wildfire smoke on a total of 188 days during the study period. A total of 18,836 asthma-related emergency room and urgent care visits occurred over the same five-year period of time, indicating that the influences of wildfire smoke and other types of air pollution on this medical condition are important to understand.

“In places like Reno, where wildfire events occur regularly during parts of the year and are expected to become more frequent in the future, an accurate understanding of the impacts of wildfire smoke on population health is critical,” Kiser said.

comparison of clear, moderate and smoky days in Stead, NV

From left to right, this series of three photos documents recent air quality conditions on clear, moderate, very smoky days in Stead, Nev. Credit: Daniel Kiser/DRI.

Additional Information:

The full text of the article “Particulate matter and emergency visits for asthma: a time-series study of their association in the presence and absence of wildfire smoke in Reno, Nevada, 2013–2018,” is available from Environmental Health: https://ehjournal.biomedcentral.com/articles/10.1186/s12940-020-00646-2

To learn more about the Renown Institute for Health Innovation, please visit: https://www.dri.edu/renown-ihi/

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About the Desert Research Institute

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, visit  www.dri.edu.

Population genetic screening shown to efficiently identify increased risk for inherited disease

Population genetic screening shown to efficiently identify increased risk for inherited disease

Healthy Nevada Project’s community-based approach reveals up to 90% of CDC Tier 1 genetic condition risks missed using clinical care guidelines

Reno, Nev. (July 27, 2020) – In a new study published today in the journal Nature Medicine, researchers behind the Healthy Nevada Project® suggest that community-based genetic screening has the potential to efficiently identify individuals who may be at increased risk for three common inherited genetic conditions known to cause several forms of cancer and increased risk for heart disease or stroke.

In 2018, the Healthy Nevada Project® (the largest, community-based population health study combining genetic, clinical, environmental, and social data) started notifying consenting study participants who have certain genetic variants that predispose them to the Centers for Disease Control and Prevention (CDC) Tier 1 genetic conditions. The study focused on identifying carriers of these conditions, which include Hereditary Breast and Ovarian Cancer, Lynch Syndrome, and Familial Hypercholesterolemia, because they are the most common conditions and early detection and treatment could significantly lower morbidity and mortality.

Initial results from almost 27,000 study participants showed that 90% of carriers of the CDC Tier 1 genetic conditions were not previously identified in a clinical setting. The authors conclude that population genetic screening would identify at-risk carriers not identified during routine care.

“Our first goal was to deliver actionable health data back to the participants of the study and understand whether or not broad population screening of CDC Tier 1 genomic conditions was a practical tool to identify at-risk individuals,” explained Joseph Grzymski, Ph.D., the principal investigator of the Healthy Nevada Project®, a research professor at the Desert Research Institute (DRI), chief scientific officer for Renown Health and lead author of the study.

“Now, two years into doing that, it is clear that the clinical guidelines for detecting risk in individuals are too narrow and miss too many at-risk individuals.”

Within the group of 26,906 Healthy Nevada Project® participants that Grzymski’s research team studied, 358 (1.33%) were carriers for CDC Tier 1 conditions. However, only 25% of those individuals met clinical guidelines for genetic screening. Additionally, more than 20% of the carriers already had a diagnosis of disease-relevant to their underlying genetic condition.

“We’re at a point now where it’s possible to do clinical-grade genetic screening at population-scale,” added James Lu, M.D. Ph.D., co-founder and chief scientific officer of Helix and senior co-author of the study. “What this study demonstrates is the potential impact of doing so. By making genetic screening available more broadly, we can help the millions of Americans who are unaware that they are living at increased risk for highly actionable, genetic conditions take action.”

Most notably, the study found that of the 273 participants who were carriers of the CDC Tier 1 genetic conditions and had clinical record information, only 22 individuals showed any previous suspicion of their underlying genetic conditions.

“For the first time, we are providing information at the individual level so study participants can make lifesaving changes to reduce their risk based on their genetics,” said Anthony Slonim, M.D., Dr.PH., FACHE, president and CEO of Renown Health and co-director of the Project® study. “We’re conducting research on the community level to develop leading-edge research on health determinants for entire neighborhoods, states and eventually, the country. Returning these results allows us to understand the prevalence of genetically programmed diseases and illnesses that we have here in Nevada and ensure we are providing the best prevention and care plans. For the individual, the return of results can be lifechanging.”

According to the CDC, early detection and intervention of Tier 1 genetic conditions could have a meaningful potential for clinical actionability and a positive impact on public health.

The Healthy Nevada Project®, which launched in 2016, offers free genetic testing to every Nevadan, aged 18 and older, interested in learning more about their health and genetic profile. With more than 50,000 study participants enrolled in four years, the Healthy Nevada Project® has become the fastest-enrolling genetic study in the world. For more about the Healthy Nevada Project® please visit healthynv.org

Renown Institute for Health Innovation is a collaboration between Renown Health – a locally governed and locally owned, not-for-profit integrated healthcare network serving Nevada, Lake Tahoe and northeast California; and the Desert Research Institute – a recognized world leader in investigating the effects of natural and humaninduced environmental change and advancing technologies aimed at assessing a changing planet. Renown IHI research teams are focused on integrating personal healthcare and environmental data with socioeconomic determinants to help Nevada address some of its most complex environmental health problems; while simultaneously expanding the state’s access to leading-edge clinical trials and fostering new connections with biotechnology and pharmaceutical companies. Learn more at Healthynv.org.

Helix is the leading population genomics company operating at the intersection of clinical care, research, and genomics. Its end-to-end platform enables health systems, life sciences companies, and payers to advance genomic research and accelerate the integration of genomic data into clinical care. Powered by one of the world’s largest CLIA / CAP next-generation sequencing labs and its proprietary Exome+Ⓡ assay, Helix supports all aspects of population genomics including recruitment and engagement, clinically actionable disease screening, return of results, and basic and translational research. In response to the COVID-19 public health crisis, Helix has launched a sensitive and scalable end-to-end COVID-19 test system to meet the needs of health systems, employers, governments, and other organizations across the country. Learn more at www.helix.com.

Media Contacts:
Justin Broglio, APR
Communications Manager, Desert Research Institute
(775) 762-8320
jbroglio@dri.edu

Sarah Bobulsky
Helix
(415) 916-2740
sarah.bobulsky@helix.com

Cassie Harris
Public Relations Business Partner, Renown Health
(775) 691-7308
news@renown.org

New study reveals key information about the microbiome of an important anticancer compound-producing Antarctic marine invertebrate

New study reveals key information about the microbiome of an important anticancer compound-producing Antarctic marine invertebrate

New study reveals key information about the microbiome of an important anticancer compound-producing Antarctic marine invertebrate

RENO, NEV.
JUNE 25, 2020

Microbiology
Melanoma
Ascidians

Could the cure for melanoma – the most dangerous type of skin cancer – be a compound derived from a marine invertebrate that lives at the bottom of the ocean? A group of scientists led by Alison Murray, Ph.D. of the Desert Research Institute (DRI) in Reno think so, and are looking to the microbiome of an Antarctic ascidian called Synoicum adareanum to better understand the possibilities for development of a melanoma-specific drug.

 Ascidians, or “sea squirts”, are primitive, sac-like marine animals that live attached to ocean-bottoms around the world, and feed on plankton by filtering seawater. S. adareanum, which grows in small colonies in the waters surrounding Antarctica, is known to contain a bioactive compound called “Palmerolide A” with promising anti-melanoma properties – and researchers believe that the compound is produced by bacteria that are naturally associated with S. adareanum.

In a new paper published this month in the journal Marine Drugs, Murray and collaborators from the University of South Florida, the Los Alamos National Laboratory, and the Université de Nantes, France, present important new findings measuring palmerolide levels across samples collected from Antarctica’s Anvers Island Archipelago and characterizing the community of bacteria that make up the microbiome of S. adareanum

“Our longer-term goal is to figure out which of the many bacteria within this species is producing palmerolide, but to do this, there is a lot we need to learn about the microbiome of S. adareanum,” Murray said. “Our new study describes many advances that we have made toward that goal over the last few years.”

Synoicum adareanum

Synoicum adareanum: The Antarctic sea squirt, Synoicum adareanum at 80’ (24 meters) lives amongst the red algae, bryozoans and starfish on the seafloor. It is a non-motile benthic species that gets its nutrition from microorganisms and organic carbon in the seawater. Its microbiome hosts a suite of different microorganisms that can provide defenses against predation and infection in some cases. Tissues of this animal were found to contain high levels of a compound that is active against melanoma, which is thought to be produced by a member of the sea squirt’s microbiome.

Credit: Bill Baker, USF

In 2008, Murray worked with Bill Baker, Ph.D., of the University of South Florida, and DRI postdoctoral researcher Christian Riesenfeld, Ph.D., to publish a study on the microbial diversity of one individual S. adareanum. Their new study builds upon this research by characterizing the microbial diversity of 63 different individuals that were collected from around Anvers Island.

Their results identify a what the researchers call the “core microbiome” of the species – a common suite of 21 bacterial taxa that were present in more than 80 percent of samples, and six bacterial taxa that were present in all 63 samples.

“It is a key “first” for Antarctic science to have been able to find and identify this core microbiome in a fairly large regional study of these organisms,” Murray said. “This is information that we need to get to the next step of identifying the producer of palmerolide.”

Another “first” for Antarctic science, and for the study of natural products in nature in general, was a comparison of palmerolide levels across all 63 samples that showed the compound was present in every specimen at high (milligram per gram specimen tissue) levels, but the researchers found no trends between sites, samples, or microbiome bacteria. Additional analysis looking at the co-occurrence relationships of the taxa across the large data set showed some of the ways that bacteria are interacting with each other and with the host species in this marine ecosystem.

 “The microbiome itself is unique in composition from other ascidians, and seems to be pretty interesting, with a lot of interaction,” Murray said. “Our study has opened the doors to understand the ecology of this system.”

From the assemblage of bacteria that the researchers have identified as making up the core microbiome of S. adareanum, they next hope to use a genomics approach to finally be able to identify which of the bacteria are producing palmerolide – an important and needed advancement toward the development of a melanoma treatment.  

“It would be a really big deal to use this compound to develop a drug for fighting melanoma, because there are just so few drugs at the moment that can be used to treat it,” Murray said. “If we can identify the bacteria that produce this chemical, and with its genome understand how to cultivate it in a laboratory setting, this would enable us to provide a sustainable supply of palmerolide that would not rely on harvesting wild populations of this species in Antarctica.”

 

Anvers Island Antarctica

Anvers Island Antarctica: Samples for microbiome characterization were collected by SCUBA divers working on the sea ice off Anvers Island, in the Antarctic Peninsula. Diving through holes cut in the sea ice requires dry suites, and relatively short dive times. (photographed Prof. Bill Baker in the hole, and his graduate student Chris Petri suited on the sled).

Credit: Maggy Amsler

DNA-stained micrograph

DNA-stained micrograph: Cultivation efforts led to isolation of a new bacterial species affiliated with the Pseudovibrio genus – a group known to produce bioactive compounds – this is the first cold-adapted member of this genus. This strain has unusual branching morphology (seen in the DNA-stained micrograph), and storage granules that appear yellow.

Credit: Eric Lundin, DRI

“It is a key “first” for Antarctic science to have been able to find and identify this core microbiome in a fairly large regional study of these organisms,” Murray said. “This is information that we need to get to the next step of identifying the producer of palmerolide.”

Additional information

The full text of the study, “Uncovering the Core Microbiome and Distribution of Palmerolide in Synoicum adareanum Across the Anvers Island Archipelago, Antarctica,” is available from Marine Drugs: https://www.mdpi.com/1660-3397/18/6/298/htm

This research was supported by the National Institute of Health, National Cancer Institute, and the National Science Foundation.

 

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About the Desert Research Institute

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

 

Media Contact

Justin Broglio
Communications Manager, Desert Research Institute
775-762-8320
Justin.Broglio@dri.edu
@DRIScience

Eruption of Alaska’s Okmok volcano linked to mysterious period of extreme cold in ancient Rome

Eruption of Alaska’s Okmok volcano linked to mysterious period of extreme cold in ancient Rome

Reno, Nev. (June 22, 2020) – An international team of scientists and historians has found evidence connecting an unexplained period of extreme cold in ancient Rome with an unlikely source: a massive eruption of Alaska’s Okmok volcano, located on the opposite side of the Earth.

Around the time of Julius Caesar’s death in 44 BCE, written sources describe a period of unusually cold climate, crop failures, famine, disease, and unrest in the Mediterranean Region – impacts that ultimately contributed to the downfall of the Roman Republic and Ptolemaic Kingdom of Egypt. Historians have long suspected a volcano to be the cause, but have been unable to pinpoint where or when such an eruption had occurred, or how severe it was.

In a new study published this week in Proceedings of the National Academy of Sciences (PNAS), a research team led by Joe McConnell, Ph.D. of the Desert Research Institute in Reno, Nev. uses an analysis of tephra (volcanic ash) found in Arctic ice cores to link the period of unexplained extreme climate in the Mediterranean with the caldera-forming eruption of Alaska’s Okmok volcano in 43 BCE.

“To find evidence that a volcano on the other side of the earth erupted and effectively contributed to the demise of the Romans and the Egyptians and the rise of the Roman Empire is fascinating,” McConnell said. “It certainly shows how interconnected the world was even 2,000 years ago.”

Landsat Image of Alaska's Okmok Caldera in the Aleutian Islands

Alaska’s Umnak Island in the Aleutians showing the huge, 10-km wide caldera (upper right) largely created by the 43 BCE Okmok II eruption at the dawn of the Roman Empire. Landsat-8 Operational Land Imager image from May 3, 2014. Credit: U.S. Geological Survey.

The discovery was initially made last year in DRI’s Ice Core Laboratory, when McConnell and Swiss researcher Michael Sigl, Ph.D. from the Oeschger Centre for Climate Change Research at the University of Bern happened upon an unusually well-preserved layer of tephra in an ice core sample and decided to investigate.

New measurements were made on ice cores from Greenland and Russia, some of which were drilled in the 1990s and archived in the U.S., Denmark, and Germany. Using these and earlier measurements, they were able to clearly delineate two distinct eruptions – a powerful but short-lived, relatively localized event in early 45 BCE, and a much larger and more widespread event in early 43 BCE with volcanic fallout that lasted more than two years in all the ice core records.

The researchers then conducted a geochemical analysis of the tephra samples from the second eruption found in the ice, matching the tiny shards with those of the Okmok II eruption in Alaska – one of the largest eruptions of the past 2,500 years.

“The tephra match doesn’t get any better,” said tephra specialist Gill Plunkett, Ph.D. from Queen’s University Belfast. “We compared the chemical fingerprint of the tephra found in the ice with tephra from volcanoes thought to have erupted about that time and it was very clear that the source of the 43 BCE fallout in the ice was the Okmok II eruption.”

Ice core samples contain records of past climate such as layers of ash from volcanic eruptions

Detailed records of past explosive volcanic eruptions are archived in the Greenland ice sheet and accessed through deep-drilling operations. Credit: Dorthe Dahl-Jensen.

Working with colleagues from the U.K., Switzerland, Ireland, Germany, Denmark, Alaska, and Yale University in Connecticut, the team of historians and scientists gathered supporting evidence from around the globe, including tree-ring-based climate records from Scandinavia, Austria and California’s White Mountains, and climate records from a speleothem (cave formations) from Shihua Cave in northeast China. They then used Earth system modeling to develop a more complete understanding of the timing and magnitude of volcanism during this period and its effects on climate and history.

According to their findings, the two years following the Okmok II eruption were some of the coldest in the Northern Hemisphere in the past 2,500 years, and the decade that followed was the fourth coldest. Climate models suggest that seasonally averaged temperatures may have been as much as 7oC (13oF) below normal during the summer and autumn that followed the 43 BCE eruption of Okmok, with summer precipitation of 50 to 120 percent above normal throughout Southern Europe, and autumn precipitation reaching as high as 400 percent of normal.

“In the Mediterranean region, these wet and extremely cold conditions during the agriculturally important spring through autumn seasons probably reduced crop yields and compounded supply problems during the ongoing political upheavals of the period,” said classical archaeologist Andrew Wilson, D.Phil. of the University of Oxford. “These findings lend credibility to reports of cold, famine, food shortage and disease described by ancient sources.”

“Particularly striking was the severity of the Nile flood failure at the time of the Okmok eruption, and the famine and disease that was reported in Egyptian sources,” added Yale University historian Joe Manning, Ph.D.  “The climate effects were a severe shock to an already stressed society at a pivotal moment in history.”

Timeline showing the Okmok II eruption in relation to European summer temperatures, volcanic sulphur and ash levels, and significant historical events in the Mediterranean from 59 to 20 BCE

Timeline showing European summer temperatures and volcanic sulphur and ash levels in relation to the Okmok II Eruption and significant historic events of the Roman Republic and Ptolemaic Kingdom from 59 to 20 BCE.

Volcanic activity also helps to explain certain unusual atmospheric phenomena that were described by ancient Mediterranean sources around the time of Caesar’s assassination and interpreted as signs or omens – things like solar halos, the sun darkening in the sky, or three suns appearing in the sky (a phenomenon now known as a parahelia, or ‘sun dog’). However, many of these observations took place prior to the eruption of Okmok II in 43 BCE, and are likely related to a smaller eruption of Mt. Etna in 44 BCE.

Although the study authors acknowledge that many different factors contributed to the fall of the Roman Republic and Ptolemaic Kingdom, they believe that the climate effects of the Okmok II eruption played an undeniably large role – and that their discovery helps to fill a knowledge gap about this period of history that has long puzzled archaeologists and ancient historians.

“People have been speculating about this for many years, so it’s exciting to be able to provide some answers,” McConnell said.


Additional information

This project received support from the National Science Foundation, the Sir Nicholas Shackleton Visiting Fellowship, Clare Hall, Cambridge and the John Fell Oxford University Press Research Fund. Additional authors from DRI included Nathan Chellman, Ph.D.

To view the full text of the article “Extreme climate after massive eruption of Alaska’s Okmok volcano in 43 BCE and effects on the late Roman Republic and Ptolemaic Kingdom”  in PNAS, please visit:  [add link]

For more information on lead author Joe McConnell, Ph.D., and his research, please visit: https://www.dri.edu/directory/joe-mcconnell/

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About the Desert Research Institute

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, visit www.dri.edu.

 

International Consortium of Scientists Propose New Naming System for Uncultivated Bacteria and Archaea

International Consortium of Scientists Propose New Naming System for Uncultivated Bacteria and Archaea

International Consortium of Scientists Propose New Naming System for Uncultivated Bacteria and Archaea

RENO, NEV.
JUNE 8, 2020

Microbiology
Nomenclature
Taxonomy

The long-standing rules for assigning scientific names to bacteria and archaea are overdue for an update, according to a new consensus statement backed by 119 microbiologists from around the globe.

Bacteria and archaea (single-celled organisms that lack cell nuclei) make up two of the three domains of life on Earth, and are named according to the International Code of Nomenclature of Prokaryotes (ICNP; the Code). At present, the Code only recognizes species that can be grown from cultures in laboratories – a requirement that has long been problematic for microbiologists who study bacteria and archaea in the wild.

Since the 1980s, microbiologists have used genetic sequencing techniques to sample and study DNA of microorganisms directly from the environment, across diverse habitats ranging from Earth’s icy oceans to deep underground mines to the surface of human skin. For a vast majority of these species, no method yet exists for cultivating them in a laboratory, and thus, according to the Code, they cannot be officially named.

“There has been a surge in recent years in genome-based discoveries for archaea and bacteria collected from the environment, but no system in place to formally name them, which is creating a lot of chaos and confusion in the field,” said Alison Murray, Ph.D., Research Professor of Biology at the Desert Research Institute (DRI) in Reno. “Being able to represent the diversity of uncultivated organisms known by their genome sequences in a common language is incredibly important.”

deep sea vent

Deep-sea hydrothermal vent chimney from the Mid-Atlantic Ridge. Many new microbial genomes have been described from these environments. 

Credit: Anna-Louise Reysenbach and Woods Hole Oceanographic Institution.

In an article published this week in the journal Nature Microbiology, Murray and her collaborators present the rationale for updating the existing regulations for naming new species of bacteria and archaea, and propose two possible paths forward.

As a first option, the group proposes formally revising the Code to include uncultivated bacteria and archaea represented by DNA sequence information, in place of the live culture samples that are currently required. As an alternative, they propose creating an entirely separate naming system for uncultivated organisms that could be merged with the Code at some point in the future. 

“For researchers in this field, the benefits of moving forward with either of these options will be huge,” said Brian Hedlund, Ph.D., Professor of Life Sciences at the University of Nevada, Las Vegas. “We will be able to create a unified list of all of the uncultivated species that have been discovered over the last few decades and implement universal quality standards for how and when a new species should be named.”

For example, researchers who use DNA sequencing to study the human microbiome – the thousands of species of Bacteria and Archaea that that live inside and on the human body – would have a means of assigning formal names to the species they identify that are not yet represented in culture collections. This would improve the ability for researchers around the world to conduct collaborative studies on topics such as connections between diet and gut bacteria in different human populations, or to build off of previous research.

Antarctic seawater microbes

This micrograph is a representative Antarctic marine sample of bacteria and archaea that has been stained with a fluorescent dye (DAPI) that binds to DNA.  A typical sample of Antarctic seawater harbors 200 to over 600 different taxa based on the diversity of 16S rRNA gene sequences. Only a small fraction of this diversity, < 1%, has been cultivated, or matches sequences of cultivated bacteria and archaea in publicly accessible databases. Through developing a nomenclature system that represents the uncultivated majority, a path for communicating diversity will benefit particularly, those microbial scientists working in natural, bio-engineered, and host-associated ecosystems. 

Credit: Alison Murray/DRI.  

A proposed update to the International Code of Nomenclature of Prokaryotes would allow scientists to assign official names to uncultivated species of Bacteria and Archaea, such as the specimens shown in this enrichment culture of heat-loving Bacteria and Archaea from a hot spring. 

Credit: Anna-Louise Reysenbach.

“It sets the framework for a path forward to provide a structured way to communicate the vast untapped biodiversity of the microbial world within the scientific community and across the public domain” said Anna-Louise Reysenbach, Ph.D., Professor of Biology at Portland State University.  “That’s why this change is so important.”

The article and proposed plans are the culmination of a series of workshops that were funded by the National Science Foundation. The next step, says Murray, is to figure out an implementation strategy for moving forward with one of the two proposed plans, while engaging the many microbiologists who contributed to this consensus statement and others around the world who want to help see this change enacted. So far, many have been eager to participate.

“This is an exciting field to be in right now because we’re describing diversity of life on Earth and uncovering new phyla just like scientists were back in the 1800s when they were still discovering larger organisms,” Murray said. “Lots of paradigms have been changing in how we understand the way the world works, and how much diversity is out there – and this is another change that needs to be made. We’re going to need to change it or we’re going to live in chaos.”

“Lots of paradigms have been changing in how we understand the way the world works, and how much diversity is out there – and this is another change that needs to be made. We’re going to need to change it or we’re going to live in chaos.”

Additional information

This project was supported by the National Science Foundation. Additional authors included DRI’s Duane Moser, Ph.D.

To view the full text of the aricle “Roadmap for naming uncultivated Archaea and Bacteria”  in Nature Microbiology, please visit: https://www.nature.com/articles/s41564-020-0733-x

For more information on lead author Alison Murray, Ph.D. and her research, please visit: https://www.dri.edu/alison-murray-research/

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About the Desert Research Institute

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

 

Media Contact

Kelsey Fitzgerald
Science Writer, Desert Research Institute
775-741-0496
Kelsey.Fitzgerald@dri.edu
@DRIScience

Prescribed Fire Science Key to Sustaining Fire We Use

Prescribed Fire Science Key to Sustaining Fire We Use

A team of leading fire scientists, including DRI’s Adam Watts, PhD, are advocating for fire research to place a priority on the area of prescribed fire science. In a recently published article in Frontiers in Fire Ecology, Watts and colleagues argue that while the vast majority of fire research focuses on issues related to suppressing wildfires, more attention must be paid to prescribed fires, which behave differently and burn more land each year than wildfire. With a greater focus on “fire we use,” authors argue, fire scientists will be able to maximize the societal and ecological benefits of prescribed burning. 

The press release below is reposted with permission from Tall Timbers Research Station in Tallahassee, Florida. 


Fire researchers provide new agenda for a future with safer fire

April 17, 2020  Leading fire researchers join together and advocate for new direction and funding to place a priority on prescribed fire science to address the global challenge of managing wildland fires. Prescribed fires are planned burns that protect communities by clearing out overgrowth that fuels out-of-control wildfires and restores and maintains plant and animal biodiversityThe March 2020 peer reviewed article is published in the journal ​​​​​​Fire Ecology and has been added to the special “Frontiers in Fire Ecology” compilation of manuscripts that represents current advances and directions. 

“You can’t just use wildfire research to address prescribed fire needs, the contexts are fundamentally different,” explains lead author Kevin Hiers from Tall Timbers Research Station. Prescribed fires are increasingly recognized as the solution to minimize impacts from wildfires and maintain ecosystem resilience, but there has been a lack of targeted science to support their expanded use. Most of the research has focused on needs and tools for wildfire suppression, despite the fact that prescribed fires cover more area each year, and there is a demonstrated need for science to guide its application and safely increase its use. 

Grants from the US Joint Fire Science Program are awarded 3:1 in favor of wildfire- to prescribed-fire-focused research, while we use 4 to 4.5 million hectares of prescribed fire in the US, versus only 2 to 4 million hectares of wildfire occurring each year. Prescribed fire is one of the most effective techniques for enabling a future in which people can live sustainably with fire. The article explains, “focus on the ‘fires we use’ has an immediate impact on the ability to safely and effectively achieve natural resource objectives for societal benefit and ecosystem resilience.” 

Watts pilots the UAS, stationed on the ground near the burn area, during the Prescribed Fire Science Consortium’s 2018 research burn, hosted by the Tall Timbers Research Station and the U.S. Forest Service. Credit: David Goodwin/Southern Fire Exchange.

The researchers, from more than ten organizations spanning the US, also highlight the important role of the individuals who actually apply prescribed fire. Prescribed fire managers bear the responsibility of choosing to start a fire, a decision with weighty career and legal consequences. Given the societal and ecological benefits of their actions, we should be arming them with the best available science and technology. As a complicating factor, climate change is challenging decades of firsthand knowledge prescribed fire managers have used to safely apply beneficial burns. The article identifies the research gaps that provide a blueprint to help fire managers worldwide protect our communities and forests.

Technology is likely to play a big role in the future of prescribed fire.  Just as flight simulators are required for airplane pilots, use of such tools for prescribed fire manager training could become a standard supplemental experience to better align fire behavior with prescribed fire planning, implementation, and outcomes.  

Tall Timbers is a research station and land conservancy in Tallahassee, Florida, with a primary research focus on the ecology and management of fire-dependent ecosystems. Author information and affiliations for the paper follow. “Prescribed fire science: the case for a refined research agenda” appears in “Fire Ecology volume 16, Article number: 11 (2020), it is open access and available at the following link https://fireecology.springeropen.com/articles/10.1186/s42408-020-0070-8. 

  • Tall Timbers Research Station, Tallahassee, Florida, 32312, USA.
    Kevin Hiers, J. Morgan Varner, Kevin Robertson & Eric M. Rowell
  • USDA Forest Service Center for Forest Disturbance Science, Athens, Georgia, 30602, USA
    Joseph J. O’Brien, Scott L. Goodrick & E. Louise Loudermilk 
  • USDA Forest Service Rocky Mountain Research Station, Missoula, Montana, 59808, USA
    Bret W. Butler & Sharon M. Hood 
  • USDA Forest Service Northern Research Station, Delaware, Ohio, 43015, USA
    Matthew Dickinson 
  • USDA Forest Service Northeastern Area State and Private Forestry, Munson, Florida, 32570, USA
    James Furman 
  • USDA Forest Service Northern Research Station, New Lisbon, New Jersey, 08064, USA
    Michael Gallagher 
  • Southern Fire Exchange, University of Florida & Tall Timbers Research Station, Tallahassee, Florida, 32312, USA
    David Godwin 
  • USDA Forest Service Rocky Mountain Research Station, Moscow, Idaho, 83844, USA
    Andrew Hudak 
  • University of Idaho, Department of Natural Resources & Society, Moscow, Idaho, 83844, USA
    Leda N. Kobziar 
  • Los Alamos National Lab, Los Alamos, New Mexico, 87545, USA
    Rodman Linn 
  • USDA Forest Service Rocky Mountain Research Station, Fort Collins, Colorado, 80526, USA
    Sarah McCaffrey 
  • USDA Forest Service Northern Research Station, Morgantown, West Virginia, 26505, USA
    Nicholas Skowronski 
  • Desert Research Institute, Reno, Nevada, 89512, USA
    Adam C. Watts 
  • USDA Forest Service Forest Products Lab, Madison, Wisconsin, 53726, USA
    Kara M. Yedinak 

### 

Media Contact: 
Contact: Brian Wiebler
Phone: 850-363-1079
Email: bwiebler@TallTimbers.org 

Emissions from cannabis growing facilities may impact indoor and regional air quality, new research shows

Emissions from cannabis growing facilities may impact indoor and regional air quality, new research shows

RENO, Nev. (Sept. 16, 2019) – The same chemicals responsible for the pungent smell of a cannabis plant may also contribute to air pollution on a much larger scale, according to new research from the Desert Research Institute (DRI) and the Washoe County Health District (WCHD) in Reno, Nev.

In a new pilot study, DRI scientists visited four cannabis growing facilities in Nevada and California to learn about the chemicals that are emitted during the cultivation and processing of cannabis plants, and to evaluate the potential for larger-scale impacts to urban air quality.

At each facility, the team found high levels of strongly-scented airborne chemicals called biogenic volatile organic compounds (BVOCs), which are naturally produced by the cannabis plants during growth and reproduction. At facilities where cannabis oil extraction took place, researchers also found very high levels of butane, a volatile organic compound (VOC) that is used during the oil extraction process.

“The concentrations of BVOCs and butane that we measured inside of these facilities were high enough to be concerning,” explained lead author Vera Samburova, Ph.D., Associate Research Professor of atmospheric science at DRI. “In addition to being potentially hazardous to the workers inside the cannabis growing and processing facilities, these chemicals can contribute to the formation of ground-level ozone if they are released into the outside air.”

Although ozone in the upper atmosphere provides protection from UV rays, ozone at ground-level is a toxic substance that is harmful for humans to breathe. Ozone can be formed when volatile organic compounds (including those from plants, automobile, and industrial sources) combine with nitrogen oxide emissions (often from vehicles or fuel combustion) in the presence of sunlight. All of these ozone ingredients are in ample supply in Nevada’s urban areas, Samburova explained – and that impacts our air quality.

“Here in our region, unfortunately, we already exceed the national air quality standard for ground-level ozone quite a few times per year,” Samburova said. “That’s why it is so important to answer the question of whether emissions from cannabis facilities are having an added impact.”

A scientist from the Desert Research Institute measures air quality inside of a cannabis growing facility. Credit: Vera Samburova/DRI. 2019.

At one of the four cannabis growing facilities visited during this study, the team measured emission rates over time, to learn about the ozone-forming potential of each individual plant. The results show that the BVOCs emitted by each cannabis plant could trigger the formation of ground-level (bad) ozone at a rate of approximately 2.6g per plant per day. The significance of this number is yet to be determined, says Samurova, but she and her team feel strongly that their findings have raised questions that warrant further study.

“This really hasn’t been studied before,” Samburova said. “We would like to collect more data on emissions rates of plants at additional facilities. We would like to take more detailed measurements of air quality emissions outside of the facilities, and be able to calculate the actual rate of ozone formation. We are also interested in learning about the health impacts of these emissions on the people who work there.”

The cannabis facility personnel that the DRI research team interacted with during the course of the study were all extremely welcoming, helpful, and interested in doing things right, Samburova noted. Next, she and her team hope to find funding to do a larger study, so that they can provide recommendations to the growing facilities and WCHD on optimum strategies for air pollution control.

“With so much growth in this industry across Nevada and other parts of the United States, it’s becoming really important to understand the impacts to air quality,” said Mike Wolf, Permitting and Enforcement Branch Chief for the WCHD Air Quality Management Division. “When new threats emerge, our mission remains the same: Implement clean air solutions that protect the quality of life for the citizens of Reno, Sparks, and Washoe County. We will continue to work with community partners, like DRI, to accomplish the mission.”

This research was funded by the WCHD and DRI. Members of the DRI team included Vera Samburova, Ph.D., Dave Campbell, M.Sc., William R. Stockwell, Ph.D., and Andrey Khlystov, Ph.D.  To view this study online, please visit: https://www.tandfonline.com/doi/full/10.1080/10962247.2019.1654038

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu. 

The Washoe County Health District has jurisdiction over all public health matters in Reno, Sparks, and Washoe County through the policy-making Washoe County District Board of Health. The District consists of five divisions: Administrative Health Services, Air Quality Management, Community and Clinical Health Services, Environmental Health Services and Epidemiology & Public Health Preparedness. To learn more, visit https://www.washoecounty.us/health/  

Lead pollution in Arctic ice shows economic impact of wars, plagues, famines from Middle Ages to present

Lead pollution in Arctic ice shows economic impact of wars, plagues, famines from Middle Ages to present

Photo: Dr. Joe McConnell and graduate student Nathan Chellman work in the ice lab at the Desert Research Institute, in Reno, Nev., on Wednesday, May 15, 2019. Photo by Cathleen Allison/Nevada Momentum.


 

RENO, Nev. (July 8, 2019) – How did events like the Black Death plague impact the economy of Medieval Europe? Particles of lead trapped deep in Arctic ice can tell us.

Commercial and industrial processes have emitted lead into the atmosphere for thousands of years, from the mining and smelting of silver ores to make currency for ancient Rome to the burning of fossil fuels today. This lead pollution travels on wind currents through the atmosphere, eventually settling on places like the ice sheet in Greenland and other parts of the Arctic.

Because of lead’s connection to precious metals like silver and the fact that natural lead levels in the environment are very low, scientists have found that lead deposits in layers of Arctic ice are a sensitive indicator of overall economic activity throughout history.

In a new study published in the Proceedings of the National Academy of Sciences, researchers from the Desert Research Institute (DRI), the University of Oxford, NILU – Norwegian Institute for Air Research, the University of Copenhagen, the University of Rochester, the Alfred Wegener Institute for Polar and Marine Research used thirteen Arctic ice cores from Greenland and the Russian Arctic to measure, date, and analyze lead emissions captured in the ice from 500 to 2010 CE, a period of time that extended from the Middle Ages through the Modern Period to the present.

This work builds on a study published by some of the same researchers in 2018, which showed how lead pollution in a single ice core from Greenland tracked the ups and downs of the European economy between 1100 BCE and 800 CE, a period which included the Greek and Roman empires.

“We have extended our earlier record through the Middle Ages and Modern Period to the present,” explained Joe McConnell, Ph.D., lead author on the study and Director of DRI’s Ultra-Trace Ice Core Chemistry Laboratory in Reno, Nevada. “Using an array of thirteen ice cores instead of just one, this new study shows that prior to the Industrial Revolution, lead pollution was pervasive and surprisingly similar across a large swath of the Arctic and undoubtedly the result of European emissions. The ice-core array provides with amazing detail a continuous record of European – and later North American – industrial emissions during the past 1500 years.”

“Developing and interpreting such an extensive array of Arctic ice-core records would have been impossible without international collaboration,” McConnell added.

The research team found that increases in lead concentration in the ice cores track closely with periods of expansion in Europe, the advent of new technologies, and economic prosperity. Decreases in lead, on the other hand, paralleled climate disruptions, wars, plagues, and famines.

“Sustained increases in lead pollution during the Early and High Middle Ages (about 800 to 1300 CE), for example, indicate widespread economic growth, particularly in central Europe as new mining areas were discovered in places like the German Harz and Erzgebirge Mountains, “McConnell noted. “Lead pollution in the ice core records declined during the Late Middle Ages and Early Modern Period (about 1300 to 1680 Ce) when plague devastated those regions, however, indicating that economic activity stalled.”

Even with ups and downs over time due to events such as plagues, the study shows that increases in lead pollution in the Arctic during the past 1500 years have been exponential.

“We found an overall 250 to 300-fold increase in Arctic lead pollution from the start of the Middle Ages in 500 CE to 1970s,” explained Nathan Chellman, a doctoral student at DRI and coauthor on the study. “Since the passage of pollution abatement policies, including the 1970 Clean Air Act in the United States, lead pollution in Arctic ice has declined more than 80 percent.”

“Still, lead levels are about 60 times higher today than they were at the beginning of the Middle Ages,” Chellman added.

This study included an array of ice cores and the research team used state-of-the-art atmospheric modeling to determine the relative sensitivity of different ice-core sites in the Arctic to lead emissions.

“Modeling shows that the core from the Russian Arctic is more sensitive to European emissions, particularly from eastern parts of Europe, than cores from Greenland,” explained Andreas Stohl, Ph.D., an atmospheric scientist at NILU and coauthor on the study. “This is why we found consistently higher levels of lead pollution in the Russian Arctic core and more rapid increases during the Early and High Middle Ages as mining operations shifted north and east from the Iberian Peninsula to Great Britain and Germany.”

Lead pollution found in 13 ice cores from three different regions of the Arctic (North Greenland, South Greenland, and the Russian Arctic) from 200 BCE to 2010 CE. Increases in lead deposition coincided with times of economic prosperity, such as the Industrial Revolution in the mid-19th century. Dramatic declines in lead pollution followed crises such as the Black Death Plague Pandemic starting about 1347 CE, as well as pollution abatement policies such as the 1970 U.S. Clean Air Act.

 

The combination of expertise on this study is unique, continuing collaboration between researchers in fields as different as ice-core chemistry and economic history. These results, the team argues, are a testament to the benefits of interdisciplinary collaboration.

“What we’re finding is interesting not just to environmental scientists who want to understand how human activity has altered the environment,” said Andrew Wilson, Ph.D., Professor of the Archaeology of the Roman Empire at Oxford and co-author on the study. “These ice-core records also are helping historians to understand and quantify the ways that societies and their economies have responded to external forces such as climate disruptions, plagues, or political unrest.”

Collection, analysis, and interpretation of the ice cores used in this study were supported by the U.S. National Science Foundation, NASA, the John Fell Oxford University Press Research Fund and All Souls College, Oxford, the German Ministry of Education and Research, the German Research Foundation, and the Desert Research Institute.

Locations of the 13 Arctic ice-core drilling sites, as well as ancient and medieval lead/silver mines throughout Europe. Atmospheric modeling shows the impact of emissions from different regions on pollution recorded in the Arctic ice cores. The Russian Arctic, for example, is relatively more sensitive to emissions from mines in eastern Europe, while North Greenland is relatively more sensitive to emissions from western Europe.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policymakers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education. Learn more at www.dri.edu, and connect with us on social media on Facebook, Instagram, and Twitter.

Media Contact:
Justin Broglio
Communications Manager, Desert Research Institute
This email address is being protected from spambots. You need JavaScript enabled to view it.”>Justin.Broglio@dri.edu
775-673-7610
@DRIscience 

Researchers identify connection between more frequent, intense heat events and deaths in Las Vegas

Researchers identify connection between more frequent, intense heat events and deaths in Las Vegas

Photo: Hotter temperatures and longer, more frequent heat waves are linked to a rising number of deaths in the Las Vegas Valley over the last 10 years.


 

Las Vegas, Nev. (June 4, 2019) – Over the last several decades, extreme heat events around the world—particularly in the North American Southwest—have gotten hotter, occurred more frequently, and lasted longer. These trends pose significant health risks to the growing number of people making cities like Las Vegas home.

A new study by faculty and undergraduate students at the Desert Research Institute (DRI), Nevada State College, and Universidad de Las Americas Puebla traces the relationship between extreme heat and mortality rates, identifying a clear correlation between heat wave episodes and heat-related deaths in Las Vegas over the last ten years.

“Current climate change projections show an increased likelihood of extreme temperature events in the Las Vegas area over the next several years,” explained Erick Bandala, Ph.D., assistant research professor at DRI and lead author on the study. “Understanding recent extreme heat trends and their relationship to health hazards is essential to protecting vulnerable populations from risk in the future.”

Researchers analyze data on computer.

Erick Bandala, PhD (left), shows a graduate student the data he and his team analyzed for this study.

Urban areas of the Southwest are of particular concern because several factors compound the health-related risks of extreme heat events. The heat-absorbing properties of common materials like asphalt exacerbate already high temperatures in cities (called the urban heat island effect), particularly at night. What’s more, populations in cities like Las Vegas are growing rapidly, especially among those 55 and older, which means that more and more people are exposed to risk.

In this study, the research team analyzed two measures of extreme heat—heat index and excess heat factor—for the Las Vegas metropolitan area in the June, July, and August months from 2007 to 2016. Heat index (HI) accounts for how the human body reacts to surface temperature and relative humidity. Excess heat factor measures (EHF) heat wave intensity in relation to historic temperature trends to account for how acclimated the public is to a given temperature threshold. Because both HI and EHF incorporate the human body’s response to extreme heat, they are ideal metrics for assessing public health impacts, and both were shown to rise over the study period.

The annual average of severe heat events per year in Las Vegas also showed significant increases in this study, from an average of 3.3 events per year from 2007-2009 to 4.7 per year in the 2010-2016 period. These findings match historic trends, which show a steady increase in severity and frequency of excess heat in Las Vegas since 1980.

Strikingly, the number of heat-related deaths in Las Vegas map onto these trends: as heat wave intensity increases, the number of heat-related deaths does, too.

Graphs of heat index and excess heat factor.

Heat Index (HI) and Excess Heat Factor (EHF) are metrics that go beyond just temperature to also account for the human body’s response to heat. This study found that rising trends in these measures tracked closely with the number of heat-related deaths in Las Vegas.

“From 2007 to 2016, there have been 437 heat-related deaths in Las Vegas, with the greatest number of those deaths occurring in 2016,” explained Bandala. “Interestingly, 2016 also shows one of the highest heat index measures over the last 35 years. This shows a clear relationship between increasingly intense heat events in our area and public health effects.”

Bandala’s team found that the subpopulation particularly at risk of heat-related deaths is adults over 50 years old—76% of the heat-related deaths in the study period were individuals in this subpopulation. Of the deaths in this group, almost all individuals also showed evidence of pre-existing heart disease. Researchers note that these findings are highly significant given that the population of adults over 50 in Las Vegas is increasing, with more retirees choosing Clark County as a retirement destination.

Only 23% of heat related deaths occurred in the subpopulation of adults aged 20 to 50 years; interestingly, the most common pre-existing condition for this group was drug and alcohol use. More research is needed to understand how heat is impacting this segment of the population, Bandala noted, because though the number of deaths in this group is comparatively smaller, it is still nearly one quarter of heat-related deaths in the Las Vegas Valley. Additionally, this subpopulation includes economically active adults.

With more intense, more frequent, and longer lasting heat events projected in the coming years, the research team hopes that the trends identified in this study can assist local decision-makers in taking steps to protect the most vulnerable groups in Las Vegas.

“This research helps us better understand the connection between the climate changes we’ve experienced in Las Vegas and their impact to public health over the last 35 years,” Bandala said. “Ideally, this data analysis will help our community adapt to the changes yet to come.”

The full study, titled “Extreme heat and mortality rates in Las Vegas, Nevada: inter-annual variations and thresholds”, is published in the International Journal of Environmental Science and Technology. The study abstract and references are available here: https://link.springer.com/article/10.1007%2Fs13762-019-02357-9 

This study is based on work supported in part by the National Science Foundation, NASA, and the Desert Research Institute. Other members of the project team include Kebret Kebede, Nikole Jonsson, Rebecca Murray, and Destiny Green, all of Nevada State College; John Mejia of DRI; and Polioptro Martinez Austria of the Universidad de Las Americas Puebla. 

Traces of Roman-era pollution stored in the ice of Mont Blanc

Traces of Roman-era pollution stored in the ice of Mont Blanc

Researchers drill ice cores from a field camp on Mont Blanc in the French Alps. Credit: B. Jourdain, L’Institut des Géosciences de l’Environnement.


 

RENO, Nev. (May 8, 2019) – Last spring, an international team of researchers led by Joe McConnell, PhD, Director of the Ultra Trace Ice Core Chemistry Laboratory at DRI’s campus in Reno, Nevada, traced significant atmospheric lead pollution from Roman-era mining and smelting of lead-silver ores in an ice core record from Greenland, providing new insights about the Roman economy.

Now working with colleagues at the Institute of Geosciences and the Environment in Grenoble, France, some members of the same research team have published findings that show a related record of pollution in an ice core from the Col du Dôme area of Mont Blanc in the French Alps.

Published in Geophysical Research Letters, the new study reveals significant atmospheric pollution from lead and antimony, another toxic heavy metal. This study is the first to document an ice core record of antimony, showing that Roman-era mining and smelting activities had implications beyond lead contamination.

 

Graph of study results.

Lead (black) and antimony (red) concentrations in ice from the Col du Dôme (CDD). On the bottom scale, age is indicated in years. Phases of increasing lead emissions were accompanied by a simultaneous rise in the presence of antimony – another toxic metal – in the alpine ice. The increases and decreases in heavy metal concentration in the ice correspond with boom times and crises in Roman-era economic history.

 

“This is the first study of antiquity-era pollution using Alpine ice,” explained lead author Susanne Preunkert, PhD, of the CNRS Institute of Geosciences and the Environment. “Our record from the Alps provides insight into the impact of ancient emissions on the present-day environment in Europe, as well as a comparison with more recent pollution linked to the use of leaded gasoline in the twentieth century.”

Compared to the lead pollution record obtained from a Greenland ice core in the previous study, which reflects heavy metal emissions from across Europe, the Mont Blanc ice core reflects influences from more local pollution sources.

“This study continues an international collaboration between ice core experts, historians, and atmospheric scientists,” said McConnell. “Cross-disciplinary research like this allows us to interpret the ice record in more detail, leading to a better understanding of the impacts of past human activities on the natural environment while also providing new, more quantitative information on those human activities.”

This research received support from the CNRS, ADEME, and the European Alpclim and Carbosol projects, as well as the Desert Research Institute.

The full study, titled “Lead and Antimony in Basal Ice From Col du Dome (French Alps) Dated With Radiocarbon: A Record of Pollution During Antiquity,” is available here.

François Maginiot of CNRS contributed to this release.

North Atlantic Ocean productivity has dropped 10 percent during Industrial era

North Atlantic Ocean productivity has dropped 10 percent during Industrial era

Researchers use a drill to extract one of the Greenland ice core samples that became the basis for this research. Credit: Joe McConnell/DRI.


RENO, Nev. (May 7, 2019) – This week, new research outlining the steady decline of phytoplankton productivity in the North Atlantic since the Industrial Revolution was published in the journal Nature. The study, titled “Industrial-era decline in subarctic Atlantic productivity,” is underpinned by data provided by Joe McConnell, Ph.D., director of DRI’s Ultra-Trace Chemistry Laboratory in Reno, Nev.

The recently published study uses measurements from twelve Greenland ice cores to trace the amount of methanesulfonic acid (MSA)—a byproduct of the emissions from large phytoplankton blooms—in the atmosphere. Since the mid-19th century, the concentration of MSA in ice core records has declined by about 10 percent, which translates to a 10 percent loss of phytoplankton. This loss coincides with steadily rising ocean surface temperatures over the same time period, which suggests that populations may decline further as temperatures continue to rise.

A full press release about these findings, originally published by MIT News, is available below.


North Atlantic Ocean productivity has dropped 10 percent during Industrial era

Phytoplankton decline coincides with warming temperatures over the last 150 years.

Jennifer Chu | MIT News Office

May 6, 2019

Virtually all marine life depends on the productivity of phytoplankton — microscopic organisms that work tirelessly at the ocean’s surface to absorb the carbon dioxide that gets dissolved into the upper ocean from the atmosphere.

Through photosynthesis, these microbes break down carbon dioxide into oxygen, some of which ultimately gets released back to the atmosphere, and organic carbon, which they store until they themselves are consumed. This plankton-derived carbon fuels the rest of the marine food web, from the tiniest shrimp to giant sea turtles and humpback whales.

Now, scientists at MIT, Woods Hole Oceanographic Institution (WHOI), and elsewhere have found evidence that phytoplankton’s productivity is declining steadily in the North Atlantic, one of the world’s most productive marine basins.

In a paper appearing today in Nature, the researchers report that phytoplankton’s productivity in this important region has gone down around 10 percent since the mid-19th century and the start of the Industrial era. This decline coincides with steadily rising surface temperatures over the same period of time.

Matthew Osman, the paper’s lead author and a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences and the MIT/WHOI Joint Program in Oceanography, says there are indications that phytoplankton’s productivity may decline further as temperatures continue to rise as a result of human-induced climate change.

“It’s a significant enough decine that we should be concerned,” Osman says. “The amount of productivity in the oceans roughly scales with how much phytoplankton you have. So this translates to 10 percent of the marine food base in this region that’s been lost over the industrial era. If we have a growing population but a decreasing food base, at some point we’re likely going to feel the effects of that decline.”

Drilling through “pancakes” of ice

Osman and his colleagues looked for trends in phytoplankton’s productivity using the molecular compound methanesulfonic acid, or MSA. When phytoplankton expand into large blooms, certain microbes emit dimethylsulfide, or DMS, an aerosol that is lofted into the atmosphere and eventually breaks down as either sulfate aerosol, or MSA, which is then deposited on sea or land surfaces by winds.

“Unlike sulfate, which can have many sources in the atmosphere, it was recognized about 30 years ago that MSA had a very unique aspect to it, which is that it’s only derived from DMS, which in turn is only derived from these phytoplankton blooms,” Osman says. “So any MSA you measure, you can be confident has only one unique source — phytoplankton.”

In the North Atlantic, phytoplankton likely produced MSA that was deposited to the north, including across Greenland. The researchers measured MSA in Greenland ice cores — in this case using 100- to 200-meter-long columns of snow and ice that represent layers of past snowfall events preserved over hundreds of years.

“They’re basically sedimentary layers of ice that have been stacked on top of each other over centuries, like pancakes,” Osman says.

The team analyzed 12 ice cores in all, each collected from a different location on the Greenland ice sheet by various groups from the 1980s to the present. Osman and his advisor Sarah Das, an associate scientist at WHOI and co-author on the paper, collected one of the cores during an expedition in April 2015.

“The conditions can be really harsh,” Osman says. “It’s minus 30 degrees Celsius, windy, and there are often whiteout conditions in a snowstorm, where it’s difficult to differentiate the sky from the ice sheet itself.”

The team was nevertheless able to extract, meter by meter, a 100-meter-long core, using a giant drill that was delivered to the team’s location via a small ski-equipped airplane. They immediately archived each ice core segment in a heavily insulated cold storage box, then flew the boxes on “cold deck flights” — aircraft with ambient conditions of around minus 20 degrees Celsius. Once the planes touched down, freezer trucks transported the ice cores to the scientists’ ice core laboratories.

“The whole process of how one safely transports a 100-meter section of ice from Greenland, kept at minus-20-degree conditions,  back to the United States is a massive undertaking,” Osman says.

Cascading effects

The team incorporated the expertise of researchers at various labs around the world in analyzing each of the 12 ice cores for MSA. Across all 12 records, they observed a conspicuous decline in MSA concentrations, beginning in the mid-19th century, around the start of the Industrial era when the widescale production of greenhouse gases began. This decline in MSA is directly related to a decline in phytoplankton productivity in the North Atlantic.

“This is the first time we’ve collectively used these ice core MSA records from all across Greenland,  and they show this coherent signal. We see a long-term decline that originates around the same time as when we started perturbing the climate system with industrial-scale greenhouse-gas emissions,” Osman says. “The North Atlantic is such a productive area, and there’s a huge multinational fisheries economy related to this productivity. Any changes at the base of this food chain will have cascading effects that we’ll ultimately feel at our dinner tables.”

The multicentury decline in phytoplankton productivity appears to coincide not only with concurrent long-term warming temperatures; it also shows synchronous variations on decadal time-scales with the large-scale ocean circulation pattern known as the Atlantic Meridional Overturning Circulation, or AMOC. This circulation pattern typically acts to mix layers of the deep ocean with the surface, allowing the exchange of much-needed nutrients on which phytoplankton feed.

In recent years, scientists have found evidence that AMOC is weakening, a process that is still not well-understood but may be due in part to warming temperatures increasing the melting of Greenland’s ice. This ice melt has added an influx of less-dense freshwater to the North Atlantic, which acts to stratify, or separate its layers, much like oil and water, preventing nutrients in the deep from upwelling to the surface. This warming-induced weakening of the ocean circulation could be what is driving phytoplankton’s decline. As the atmosphere warms the upper ocean in general, this could also further the ocean’s stratification, worsening phytoplankton’s productivity.

“It’s a one-two punch,” Osman says. “It’s not good news, but the upshot to this is that we can no longer claim ignorance. We have evidence that this is happening, and that’s the first step you inherently have to take toward fixing the problem, however we do that.”

This research was supported in part by the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), as well as graduate fellowship support from the US Department of Defense Office of Naval Research.

Reprinted with permission of MIT News.

Forest fires accelerating snowmelt across western U.S., new study finds

Forest fires accelerating snowmelt across western U.S., new study finds

Kelly Gleason, assistant professor of environmental science and management at Portland State University, and crew head out in a recently burned forest to collect snow samples. Credit: Kelly Gleason/Portland State University


 

RENO, Nev. (May 2, 2019) – Forest fires are causing snow to melt earlier in the season, a trend occurring across the western U.S. that may affect water supplies and trigger even more fires, according to a new study by a team of researchers at Portland State University (PSU), the Desert Research Institute (DRI), and the University of Nevada, Reno.

It’s a cycle that will only be exacerbated as the frequency, duration, and severity of forest fires increase with a warmer and drier climate.

The study, published May 2 in the journal Nature Communications, provides new insight into the magnitude and persistence of forest fire disturbance on critical snow-water resources.

Researchers found that more than 11 percent of all forests in the West are currently experiencing earlier snowmelt and snow disappearance as a result of fires.

The team used state-of-the-art laboratory measurements of snow samples, taken in DRI’s Ultra-Trace Ice Core Analytical Laboratory in Reno, Nevada, as well as radiative transfer and geospatial modeling to evaluate the impacts of forest fires on snow for more than a decade following a fire. They found that not only did snow melt an average five days earlier after a fire than before all across the West, but the accelerated timing of the snowmelt continued for as many as 15 years.

“This fire effect on earlier snowmelt is widespread across the West and is persistent for at least a decade following fire,” said Kelly Gleason, the lead author and an assistant professor of environmental science and management in PSU’s College of Liberal Arts and Sciences.

Gleason, who conducted the research as a postdoctoral fellow at the Desert Research Institute, and her team cite two reasons for the earlier snowmelt.

First, the shade provided by the tree canopy gets removed by a fire, allowing more sunlight to hit the snow. Secondly and more importantly, the soot — also known as black carbon — and the charred wood, bark and debris left behind from a fire darkens the snow and lowers its reflectivity. The result is like the difference between wearing a black t-shirt on a sunny day instead of a white one.

In the last 20 years, there’s been a four-fold increase in the amount of energy absorbed by snowpack because of fires across the West.

Research team in snowy forest

Burned forests shed soot and burned debris that darken the snow surface and accelerate snowmelt for years following fire. Image Credit: Nathan Chellman/DRI.

“Snow is typically very reflective, which is why it appears white, but just a small change in the albedo or reflectivity of the snow surface can have a profound impact on the amount of solar energy absorbed by the snowpack,” said co-author Joe McConnell, a research professor of hydrology and head of the Ultra-Trace Ice Core Analytical Laboratory at DRI. “This solar energy is a key factor driving snowmelt.”

For Western states that rely on snowpack and its runoff into local streams and reservoirs for water, early snowmelt can be a major concern.

“The volume of snowpack and the timing of snowmelt are the dominant drivers of how much water there is and when that water is available downstream,” Gleason said. “The timing is important for forests, fish, and how we allocate reservoir operations; in the winter, we tend to control for flooding, whereas in the summer, we try and hold it back.”

Early snowmelt is also likely to fuel larger and more severe fires across the West, Gleason said.

“Snow is already melting earlier because of climate change,” she said. “When it melts earlier, it’s causing larger and longer-lasting fires on the landscape. Those fires then have a feedback into the snow itself, driving an even earlier snowmelt, which then causes more fires. It’s a vicious cycle.”

Gleason will continue to build on this research in her lab at PSU. She’s in the first year of a grant from NASA that’ll look at the forest fire effects on snow albedo, or how much sunlight energy its surface reflects back into the atmosphere.

Funding for the study was provided by the Sulo and Aileen Maki Endowment at the Desert Research Institute. Co-authors also included Monica Arienzo and Nathan Chellman from DRI and Wendy Calvin from the University of Nevada, Reno.

The full paper, “Four-fold increase in solar forcing on snow in western U.S. burned forests since 1999,” is available here.

Cristina Rojas of PSU’s College of Liberal Arts and Sciences contributed to this release.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education.

As Oregon’s only urban public research university, Portland State offers tremendous opportunity to 27,000 students from all backgrounds. Our mission to “Let Knowledge Serve the City” reflects our dedication to finding creative, sustainable solutions to local and global problems. Our location in the heart of Portland, one of America’s most dynamic cities, gives our students unmatched access to career connections and an internationally acclaimed culture scene. “U.S. News & World Report” ranks us among the nation’s most innovative universities.

DRI researchers successfully remove harmful hormones from Las Vegas wastewater using green algae

DRI researchers successfully remove harmful hormones from Las Vegas wastewater using green algae

Xuelian Bai, Ph.D., Assistant Research Professor of Environmental Sciences, works with an algae sample in the Environmental Engineering Laboratory at the Desert Research Institute in Las Vegas. Credit: Sachiko Sueki.


 

LAS VEGAS, Nev. (April 8, 2019) – A common species of freshwater green algae is capable of removing certain endocrine disrupting chemicals (EDCs) from wastewater, according to new research from the Desert Research Institute (DRI) in Las Vegas.

EDCs are natural hormones and can also be found in many plastics and pharmaceuticals. They are known to be harmful to wildlife, and to humans in large concentrations, resulting in negative health effects such as lowered fertility and increased incidence of certain cancers. They have been found in trace amounts (parts per trillion to parts per billion) in treated wastewater, and also have been detected in water samples collected from Lake Mead.

In a new study published in the journal Environmental Pollution, DRI researchers Xuelian Bai, Ph.D., and Kumud Acharya, Ph.D., explore the potential for use of a species of freshwater green algae called Nannochloris to remove EDCs from treated wastewater.

“This type of algae is very commonly found in any freshwater ecosystem around the world, but its potential for use in wastewater treatment hadn’t been studied extensively,” explained Bai, lead author and Assistant Research Professor of environmental sciences with the Division of Hydrologic Sciences at DRI. “We wanted to explore whether this species might be a good candidate for use in an algal pond or constructed wetland to help remove wastewater contaminants.”

Samples of Nannochloris grow in the Environmental Engineering Laboratory at DRI. This species of green algae was found to be capable of removing certain types of endocrine disrupting chemicals from treated wastewater. Credit: Xuelian Bai/DRI.

Samples of Nannochloris grow in the Environmental Engineering Laboratory at DRI. This species of green algae was found to be capable of removing certain types of endocrine disrupting chemicals from treated wastewater. Credit: Xuelian Bai/DRI.

During a seven-day laboratory experiment, the researchers grew Nannochloris algal cultures in two types of treated wastewater effluents collected from the Clark County Water Reclamation District in Las Vegas, and measured changes in the concentration of seven common EDCs.

In wastewater samples that had been treated using an ultrafiltration technique, the researchers found that the algae grew rapidly and significantly improved the removal rate of three EDCs (17β-estradiol, 17α-ethinylestradiol and salicylic acid), with approximately 60 percent of each contaminant removed over the course of seven days. In wastewater that had been treated using ozonation, the algae did not grow as well and had no significant impact on EDC concentrations.

One of the EDCs examined in the study, triclosan, disappeared completely from the ultrafiltration water after seven days, and only 38 percent remained in the ozonation water after seven days – but this happened regardless of the presence of algae, and was attributed to breakdown by photolysis (exposure to light).

“Use of algae for removing heavy metals and other inorganic contaminants have been extensively studied in the past, but for removing organic pollutants has just started,” said Acharya, Interim Vice President for Research and Executive Director of Hydrologic Sciences at DRI. “Our research shows both some of the potential and also some of the limitations for using Nannochloris to remove EDCs from wastewater.”

Although these tests took place under laboratory conditions, a previous study by Bai and Acharya that published in November 2018 in the journal Environmental Science and Pollution Research examined the impacts of these same seven EDCs on quagga mussels (Dreissena bugensis) collected from Lake Mead. Their results showed that several of the EDCs (testosterone, bisphenol A, triclosan, and salicylic acid) were accumulating in the body tissues of the mussels.

Researcher examines a sample of quagga mussels collected from Lake Mead. A recent study by Bai and Acharya found that endocrine disrupting chemicals are accumulating in the body tissues of these mussels. Credit: Xuelian Bai.

Researcher examines a sample of quagga mussels collected from Lake Mead. A recent study by Bai and Acharya found that endocrine disrupting chemicals are accumulating in the body tissues of these mussels. Credit: Xuelian Bai.

“Algae sit at the base of the food web, thereby providing food for organisms in higher trophic levels such as quagga mussels and other zooplantkons,” Bai said. “Our study clearly shows that there is potential for these contaminants to biomagnify, or build up at higher levels of the food chain in the aquatic ecosystem.”

Bai is now working on a new study looking for antibiotic resistance in genes collected from the Las Vegas Wash, as well as a study of microplastics in the Las Vegas Wash and Lake Mead. Although Las Vegas’s treated wastewater meets Clean Water Act standards, Bai hopes that her research will draw public attention to the fact that treated wastewater is not 100 percent clean, and will also be helpful to utility managers as they develop new ways to remove untreated contaminants from wastewater prior to release.

“Most wastewater treatment plants are not designed to remove these unregulated contaminants in lower concentrations, but we know they may cause health effects to aquatic species and even humans, in large concentrations,” Bai said. “This is concerning in places where wastewater is recycled for use in agriculture or released back into drinking water sources.”

Bai’s research was funded by the Desert Research Institute Maki Endowment, the U.S. Geological Survey, and the Nevada Water Resources Research Institute. The studies mentioned in this release are available from Environmental Pollution and Environmental Science and Pollution Research journals:

Bai, X. and Kumud Acharya. 2019. Removal of seven endocrine disrupting chemicals (EDCs) from municipal wastewater effluents by a freshwater green alga. Environmental Pollution. 247: 534-540. Available: https://www.sciencedirect.com/science/article/pii/S0269749118347894

Bai, X. and Kumud Acharya. 2018. Uptake of endocrine-disrupting chemicals by quagga mussels (Dreissena bugensis) in an urban-impacted aquatic ecosystem. Environmental Science and Pollution Research. 26: 250-258. Available: https://link.springer.com/article/10.1007/s11356-018-3320-4

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as one of eight institutions in the Nevada System of Higher Education.

Study provides new insight into how microbes process nitrogen

Study provides new insight into how microbes process nitrogen

Reno, Nev. (Feb. 19, 2019): Microbes play a key role in Earth’s nitrogen cycle, helping to transform nitrogen gas from the atmosphere back and forth into organic forms of nitrogen that can be used by plants and animals.

New research from the Desert Research Institute in Reno, Nev. provides new insight into how this process happens, through the examination of a unique species of microbe called Intrasporangium calvum that was found in a contaminated groundwater well at Oak Ridge National Laboratory Field Research Station in Tennessee.

The study, which published in Frontiers in Microbiology in January, examined the response of I. calvum to different concentrations of environmental resources and how those differences impacted the microbe’s nitrogen cycling ability. The study team also investigated the evolution of this microbe, the biochemistry behind the reactions, and how each of those factors interact with the environment.

Although most microbes perform just one step in the nitrogen cycle – converting nitrogen gas (N2) from the atmosphere to ammonia (NH3) in the soil, for example – the research team discovered that I. calvum could perform two types of reactions: respiratory ammonification and denitrification. Respiratory ammonification retains nitrogen in an ecosystem as ammonium in the soil or water, while denitrification sends nitrogen on a path back to the atmosphere as a gas.

“The microbe that we studied is unique because it can essentially ‘breathe’ in nitrogen and then send the nitrogen along one of two pathways, ‘exhaling’ either ammonium or nitrous oxide,” said David Vuono, Ph.D., postdoctoral researcher fellow with DRI’s Division of Earth and Ecosystem Sciences and Applied Innovation Center, and lead author of the new study. “This is kind of like humans breathing in oxygen and then having the ability to exhale either carbon dioxide or methane.”

Sample bottles of I. calvum are sterilized via flame in the Genomics Laboratory at DRi. February 2019. Credit: DRI.

With the ability to perform more than one type of reaction – either sending nitrogen back to the atmosphere or retaining it in the soil or water – Vuono and his team wondered what would trigger the microbe to select one pathway versus the other. Previous studies had concluded that the ratio of carbon (C) to nitrate (NO3) in the surrounding environment was the determining factor, but Vuono wondered if the story wasn’t actually more complex.

In this study, Vuono and his team looked beyond the C:NO3ratio to investigate the importance of the overall concentration of each nutrient. They tested the response of I. calvumunder conditions of both high and low resource availability, while keeping the ratio of C:NO3at a constant level.

According to their findings, it is the resource concentration, rather than the C:NO3ratio, that determines pathway selection. When grown under low carbon concentrations, the team found that these microbes were more likely to process nitrogen by ammonification; under high carbon concentrations, denitrification prevailed.

“As we learned, the concentration of nutrients available to these microbes is what determines where the nitrogen ends up, whether it takes a pathway back towards the atmosphere or returns to ammonium,” Vuono explained. “That is a really important distinction, because depending on the environment that you’re in, you may want to remove nitrogen or you may want to retain it.”

In a waterway, for example, high levels of nitrogen can cause algae blooms and dead zones; by creating conditions that favor denitrification, it is possible that microbes could be triggered to send nitrogen back to the atmosphere. In an agricultural field, on the other hand, nitrogen deficiencies in the soil can lead to poor plant growth; by creating conditions that would promote respiratory ammonification, microbes could be prompted to retain nitrogen in the soils, eliminating or lessening the need for chemical fertilizers.

David Vuono, Ph.D., prepares a sample of I. calvum for analysis in the Laboratory of Molecular Responses at DRI. February 2019. Credit: DRI.

This study was funded by the Nevada Governor’s Office of Economic Development (GOED), the Desert Research Institute postdoctoral research fellowship program, Ecosystems and Networks Integrated with Genes and Molecular Assemblies (ENIGMA), and Oak Ridge National Laboratory (US Department of Energy, Office of Science, Office of Biological and Environmental Research).

Other DRI scientists who contributed to this study included Robert Read, John A. Arnone III, Iva Neveux, Evan Loney, David Miceli, and Joseph Grzymski.

The full study, titled Resource Concentration Modulates the Fate of Dissimilated Nitrogen in a Dual-Pathway Actinobacterium, is available online from Frontiers in Microbiology (22 January 2019): https://doi.org/10.3389/fmicb.2019.00003

New research shows impact of using shared language and building public trust in weather forecasts

New research shows impact of using shared language and building public trust in weather forecasts

Reno, Nev. (January 22, 2019): For meteorologists, effectively communicating weather forecasts and their related dangers is essential in maintaining the health, safety, and resilience of communities. A new study published by a team of researchers from the University of Nevada, Reno (UNR), the Desert Research Institute (DRI), and the National Weather Service (NWS) Reno suggests that effective communication isn’t only about sharing information on upcoming weather events—it’s about building trust and common ground between forecasters and the public.

A common focus of science communication research is the difficulty of communicating technical information about weather forecasts to the public, including the likelihood that the forecasted events will actually come to pass. However, personal risks and uncertainty about potential impacts also affect how people respond to and act upon information about subjects like weather forecasts.

In a study published in the Bulletin of the American Meteorological Society, researchers sought to investigate the effect of personal uncertainties on people’s responses to weather forecasts by analyzing posts by the NWS Reno on Facebook. Researchers analyzed a total of 470 Facebook posts by the NWS Reno and 6,467 user comments on the posts about high impact weather events from January to May 2017. This range overlapped with the Reno area’s record wet period during from October 2016 to April 2017, a time when the region’s residents were impacted by several high impact weather events.

The team’s analysis showed that the public’s uncertainty about weather forecasts isn’t usually technical—more often, it’s personal.

“The NWS Reno’s Facebook community engages far less with the technical uncertainties of forecasts than with the personal risks implied in those forecasts,” said Kathryn Lambrecht, Ph.D., lead author on the study and Assistant Director of the Composition and Communication in the Disciplines program at UNR. “People in this community frequently use the NWS posts to share their own experiences with weather, express concern, and reach out to family and friends, not to calculate the technical likelihood of a forecast.”

What’s more, this study’s results showed that posts that used “commonplaces”—or expressions of common values or norms among a community—generated the strongest responses, many of which acknowledged a connection or understanding between the NWS Reno and its followers on Facebook.

Graphic from the NWS Reno Facebook page

Most of the population in the Reno area is located in valleys where it only snows occasionally. Feet of snow can fall in the higher elevations of the Sierra Nevada with the Reno area receiving little to no snow accumulation, so the public often asks “Is it really going to snow down here [in the valley]?” The commonplace “down here” was added to what became a widely shared and commented forecast graphic on the NWS Reno Facebook page.

“Commonplaces speak the language of the community,” explained Ben Hatchett, co-author on the study and assistant professor of atmospheric science at DRI. “We found that the posts using shared language in forecasts helped build a feeling of solidarity among the NWS Reno and followers. Perhaps more importantly, this encouraged sharing of forecasts between users through tagging and comments, broadening the distribution of the posts.”

Because high-impact weather events can severely impact life and property, it is imperative that the public trusts the information coming from the National Weather Service or emergency managers. Commonplaces, this study revealed, can be an effective way for forecasters to build trust with the community and encourage behavioral changes—like changing driving routes or stocking up on sandbags—that ultimately promote public safety.

From here, the team is considering applying for more funding in order to scale up their research and see if their results are consistent in other regions beyond the Reno area.

Researchers on this study included a meteorologist, an atmospheric scientist, a STEM education expert, and a pair of rhetoricians, scholars who study how communication forms communities—an unusual combination of disciplines.

“Past research has shown that science communication benefits from bringing together multiple types of expertise,” Hatchett said. “Our group came together organically, and the result was a highly transdisciplinary project. Personally, I think it is one of the most unique and collaborative projects I have been a part of, which made it even more fun.”

This project was supported by the Nevada NASA Space Grant Consortium and the Desert Research Institute.

The full study, titled “Improving Visual Communication of Weather Forecasts with Rhetoric” is available online from the Bulletin of the American Meteorological Society: https://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-18-0186.1

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI is one of eight institutions in the Nevada System of Higher Education.

Nevada’s land-grant university founded in 1874, the University of Nevada, Renoranks in the top tier of best national universities by U.S. News and World Report and is steadily growing in enrollment, excellence and reputation. The University serves nearly 22,000 students. Part of the Nevada System of Higher Education, the University is home to the University of Nevada, Reno School of Medicine, University of Nevada Cooperative Extension and Wolf Pack Athletics. Through a commitment to world-improving research, student success and outreach benefiting the communities and businesses of Nevada, the University has impact across the state and around the world. For more information, visit www.unr.edu.

Research team develops first lidar-based method for measuring snowpack in mountain forests

Research team develops first lidar-based method for measuring snowpack in mountain forests

Reno, Nev. (Jan. 22, 2018): Many Western communities rely on snow from mountain forests as a source of drinking water – but for scientists and water managers, accurately measuring mountain snowpack has long been problematic. Satellite imagery is useful for calculating snow cover across open meadows, but less effective in forested areas, where the tree canopy often obscures the view of conditions below.

Now, a new technique for measuring snow cover using a laser-based technology called lidar offers a solution, essentially allowing researchers to use lasers to “see through the trees” and accurately measure the snow that lies beneath the forest canopy. 

In a new study published in Remote Sensing of the Environment, an interdisciplinary team of researchers from Desert Research Institute (DRI), the University of Nevada, Reno (UNR), the California Institute of Technology’s Jet Propulsion Laboratory, and California State University  described the first successful use of lidar to measure snow cover under forested canopy in the Sierra Nevada.

“Lidar data is gathered by laser pulses shot from a plane, some of which are able to pass light through the tree canopy right down to the snow surface and create a highly accurate three-dimensional map of the terrain underneath,” explained lead author Tihomir Kostadinov, Ph.D., of California State University San Marcos, who completed the research while working as a postdoctoral researcher at DRI. “Passive optical satellite imaging techniques, which are essentially photographs taken from space, don’t allow you to see through the trees like this.  We are only starting to take full advantage of all the information in lidar.”

Researcher surveys snowpack at Sagehen Creek Field Station

Rowan Gaffney (UNR) surveying the amount of snow at Sagehen Creek Field Station during the NASA airborne campaigns in March 2016. Credit: A. Harpold.

In this study, researchers worked with NASA’s Airborne Snow Observatory to collect lidar data at the University of California, Berkeley’s Sagehen Creek Field Station in the Sierra Nevada by aircraft on three dates during spring of 2016 when snow was present. Additional lidar data and ground measurements facilities by the long-term operation of Sagehen Creek field station were critical to the success of the study.

Analysis of the datasets revealed that the lidar was in fact capable of detecting snow presence or absence both under canopy and in open areas, so long as areas with low branches were removed from the analysis. On-the-ground measurements used distributed temperature sensing with fiber optic cables laid out on the forest floor to verify these findings.

Tree canopies interact with the snowpack in complex ways, causing different accumulation and disappearance rates under canopies as compared to open areas. With the ability to use lidar data to measure snow levels beneath trees, snow cover estimates used by scientists and resource managers can be made more accurate. The importance of this advance could be far reaching, said team member Rina Schumer, Ph.D., Assistant Vice President of Academic and Faculty Affairs at DRI.

“In the Sierra Nevada, April 1st snow cover is what is used to estimate water supply for the year,” Schumer said. “Being able to more accurately assess snow cover is important for California and Nevada, but also all mountainous areas where snowpack is essential to year-round water supply.”

Snow cover estimates are also used by hydrologists for streamflow forecasts and reservoir management. Snow cover data is important to ecologists and biologists for understanding animal migration, wildlife habitat, and forest health, and it is useful to the tourism and recreation industry for informing activities related to winter snow sports.

Researcher surveys snow under forest canopy at Sagehen Creek Field Station.

Rose Petersky (UNR) surveying the amount of snow under the forest canopy at Sagehen Creek Field Station during the NASA airborne campaigns in April 2016. The photo clearly shows the reduced snow cover under the canopy that is difficult to measure with satellites. Credit: A. Harpold.

Although lidar data is currently collected via airplane and not easily accessible by all who might like to use it, the study team believes that information gleaned from this study could be used to correct data derived from satellite imagery, which is already widely available from NASA’s MODIS sensor and NASA/USGS’s Landsat satellites.

“This is proof of concept for the method that we think could really expand the extent that we measure snow at high resolution in forests,” said team member Adrian Harpold, Ph.D., Assistant Professor with the Department of Natural Resources at UNR. “I’m now working with a student to extend this approach across multiple sites to improve our understanding of the relationship between snow cover in the open versus under the tree canopy. Then, we hope to use that information to correct and improve satellite remote sensing in forested areas.”

This study was part of a larger NASA EPSCoR project titled Building Capacity in Interdisciplinary Snow Sciences for a Changing World, which aimed to develop new research, technology, and education capacity in Nevada for the interdisciplinary study of snowpack. Objectives included an educational goal of training the next generation of scientists.

“This project brought together people who look at snow from different scientific perspectives, and generated a conversation amongst us,” said Alison Murray, Ph.D., Research Professor at DRI and principal investigator of the NASA EPSCoR project. “In addition to bringing together expertise from three institutions in Nevada (DRI, UNR, and UNLV) in hydrology, remote sensing, geosciences, atmospheric chemistry and snow associated life, we developed strategic alliances with NASA’s airborne snow survey. Where the Nevada researchers might have been studying snow on our own, this interdisciplinary project allowed us to look at snow in an integrated fashion and make some important advances.”

The full study, titled Watershed-scale mapping of fractional snow cover under conifer forest canopy using lidar, is available online from Remote Sensing of the Environment: https://www.sciencedirect.com/science/article/abs/pii/S0034425718305467

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. Learn more at www.dri.edu, and connect with us on social media on FacebookInstagram and Twitter. 

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New study identifies atmospheric conditions that precede wildfires in the Southwest

New study identifies atmospheric conditions that precede wildfires in the Southwest

Reno, Nev. (January 3, 2018): To protect communities in arid landscapes from devastating wildfires, preparation is key. New research from the Desert Research Institute (DRI) in Reno may aid in the prevention of large fires by helping meteorologists and fire managers in the Southwestern U.S. to forecast periods of likely wildfire activity.

Each summer, from June through September, a weather pattern called the North American monsoon brings thunderstorms to the Southwestern U.S., with lightning that often sparks wildfires.

The new study, which published in the International Journal of Climatology, examined twenty common weather patterns that occur during the North American monsoon season, and identified relationships between certain weather patterns and times of increased fire activity.

One of the most problematic weather patterns, the team learned, was when dry and windy conditions gave way to lightning storms in May and June – a time when fuels tended to be at their driest and monsoon rains had not yet soaked the region with added moisture. When lightning storms were followed by another hot, dry, windy period, increased fire activity was even more likely.

“A lot of fire meteorologists know from experience that this is how things happen, but our study actually quantified it and showed how the patterns unfold,” said lead author Nick Nauslar, Ph.D., who completed this research while working as a graduate student at DRI under Tim Brown, Ph.D. “No one had ever really looked at large fire occurrence in the Southwest and how it related to atmospheric patterns.”

To identify problematic weather patterns, Nauslar and his team looked at monsoon season weather data collected from April through September over the 18-year period from 1995-2013. They then classified wildfire activity over the same period into days or events that were considered “busy” by fire managers in their study area, and used an analysis technique called Self-Organizing Maps to detect relationships between the two datasets.

In addition to identifying relationships between specific weather patterns and fire activity, their analysis also looked for patterns in wildfire occurrence and fire size throughout the season. Analysis of more than 84,000 wildfires showed that although July was the month that the most wildfires occurred, wildfires that occurred during the month of June (prior to the arrival of much monsoonal moisture) were more likely to develop into large fires. In July and August, when the heaviest monsoonal precipitation typically occurs, the percentage of fires that developed into large fires decreased.

“Our goal with this study was to provide fire weather meteorologists in the region with information to help inform fire forecasts, and I think we were able to identify some important patterns,” said Brown, Director of the Western Regional Climate Center at DRI.

Nauslar, who is now employed as a mesoscale assistant and fire weather forecaster for the National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center in Norman, Oklahoma, hopes that the findings of this study will help fire managers in the Southwest to proactively identify periods when wildfires are more likely to occur, and to allocate firefighting resources accordingly.

“I think a lot of what we learned confirms forecaster experience about the types of atmospheric patterns that are problematic with regard to wildfire occurrence in the Southwest,” Nauslar said. “I hope that people in operations can really use this information, and help refine it and build upon it.

Other DRI scientists who contributed to this research included Benjamin Hatchett, Ph.D., Michael Kaplan, Ph.D., and John Mejia, Ph.D. The full study, titled “Impact of the North American monsoon on wildfire activity in the southwest United States,” is available online from the International Journal of Climatology: https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.5899

 

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. Learn more at www.dri.edu, and connect with us on social media on FacebookInstagram and Twitter. 

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Data from DRI ice core lab shows rapid melting of Greenland ice sheet

Data from DRI ice core lab shows rapid melting of Greenland ice sheet

Reno, Nev. (Dec. 5, 2018): The melting of the Greenland ice sheet has increased rapidly in response to Arctic warming, and is likely to continue to do so into the future, according to new research from an international team of scientists including Joe McConnell, Ph.D., of the Desert Research Institute in Reno. Among other findings, their research shows a 250 to 575 percent increase in melt intensity over the last 20 years.

This study team utilized ice cores to reconstruct past melting rates from the present day back to the 1600s, producing the first continuous, multi-century record of surface melt intensity and runoff from the Greenland ice sheet. Previous studies have utilized satellite observations, which only go back to 1978.

McConnell, who is a research professor of hydrology and head of the Ultra-Trace Ice Core Analytical Laboratory at DRI, first became involved in the study in 2003 when his research group drilled and analyzed the contents of a 150-meter (492-foot) ice core from west-central Greenland. This ice core, known as “D5”, was then used by Sarah Das, Ph.D. from Woods Hole Oceanographic Institution (WHOI) to develop the record of surface melting rates used in this study.

In a subsequent 2016 collaboration with WHOI researchers, McConnell’s group also used DRI’s unique continuous ice-core analytical system to analyze a 115-meter (377-foot) ice core known as “NU”, which was collected in 2015 by the study’s lead author Luke Trusel and colleagues. The detailed DRI measurements of more than 20 elements and chemical species in both the D5 and NU ice cores enabled precise dating of the records that underpin the new findings.

Recovering an ice core from west Greenland. Credit: Sarah Has/Woods Hole Oceanographic Institution

Recovering an ice core from west Greenland. Credit: Sarah Has/Woods Hole Oceanographic Institution

The study, titled “Nonlinear Rise in Greenland Runoff in Response to Post-industrial Arctic Warming”, was published in the journal Nature in on December 5, 2018: https://doi.org/10.1038/s41586-018-0752-4. A detailed press release from Woods Hole Oceanographic Institution is below.


 Greenland Ice Sheet Melt ‘Off the Charts’ Compared with Past Four Centuries

Surface melting across Greenland’s mile-thick ice sheet began increasing in the mid-19th century and then ramped up dramatically during the 20th and early 21st centuries, showing no signs of abating, according to new research published Dec. 5, 2018, in the journal Nature. The study provides new evidence of the impacts of climate change on Arctic melting and global sea level rise.

“Melting of the Greenland Ice Sheet has gone into overdrive. As a result, Greenland melt is adding to sea level more than any time during the last three and a half centuries, if not thousands of years,” said Luke Trusel, a glaciologist at Rowan University’s School of Earth & Environment and former post-doctoral scholar at Woods Hole Oceanographic Institution, and lead author of the study. “And increasing melt began around the same time as we started altering the atmosphere in the mid-1800s.”

“From a historical perspective, today’s melt rates are off the charts, and this study provides the evidence to prove this,” said Sarah Das, a glaciologist at Woods Hole Oceanographic Institution (WHOI) and co-author of the study. “We found a fifty percent increase in total ice sheet meltwater runoff versus the start of the industrial era, and a thirty percent increase since the 20th century alone.”

Meltwater lakes on the Greenland ice sheet. Credit: Sarah Das/Woods Hole Oceanographic Institution.

Meltwater lakes on the Greenland ice sheet. Credit: Sarah Das/Woods Hole Oceanographic Institution.

Ice loss from Greenland is one of the key drivers of global sea level rise. Icebergs calving into the ocean from the edge of glaciers represent one component of water re-entering the ocean and raising sea levels. But more than half of the ice-sheet water entering the ocean comes from runoff from melted snow and glacial ice atop the ice sheet. The study suggests that if Greenland ice sheet melting continues at “unprecedented rates”—which the researchers attribute to warmer summers—it could accelerate the already fast pace of sea level rise.

“Rather than increasing steadily as climate warms, Greenland will melt increasingly more and more for every degree of warming. The melting and sea level rise we’ve observed already will be dwarfed by what may be expected in the future as climate continues to warm,” said Trusel.

To determine how intensely Greenland ice has melted in past centuries, the research team used a drill the size of a traffic light pole to extract ice cores from the ice sheet itself and an adjacent coastal ice cap, at sites more than 6,000 feet above sea level.  The scientists drilled at these elevations to ensure the cores would contain records of past melt intensity, allowing them to extend their records back into the 17th century.

During warm summer days in Greenland, melting occurs across much of the ice sheet surface. At lower elevations, where melting is the most intense, meltwater runs off the ice sheet and contributes to sea level rise, but no record of the melt remains. At higher elevations, however, the summer meltwater quickly refreezes from contact with the below-freezing snowpack sitting underneath. This prevents it from escaping the ice sheet in the form of runoff. Instead, it forms distinct icy bands that stack up in layers of densely packed ice over time.

The core samples were brought back to ice core labs at the U.S. National Science Foundation Ice Core Facility in Denver, Colo., WHOI in Woods Hole, Mass., Wheaton College in Norton, Mass., and the Desert Research Institute in Reno, Nev. where the scientists measured physical and chemical properties along the cores to determine the thickness and age of the melt layers. Dark bands running horizontally across the cores, like ticks on a ruler, enabled the scientists to visually chronicle the strength of melting at the surface from year to year. Thicker melt layers represented years of higher melting, while thinner sections indicated years with less melting.

Iceberg in Disko Bay, west Greenland. Credit Luke Trusel/Rowan University.

Iceberg in Disko Bay, west Greenland. Credit Luke Trusel/Rowan University.

Combining results from multiple ice cores with observations of melting from satellites and sophisticated climate models, the scientists were able to show that the thickness of the annual melt layers they observed clearly tracked not only how much melting was occurring at the coring sites, but also much more broadly across Greenland.  This breakthrough allowed the team to reconstruct meltwater runoff at the lower-elevation edges of the ice sheet—the areas that contribute to sea level rise.

Ice core records provide critical historical context because satellite measurements—which scientists rely on today to understand melting rates in response to changing climate—have only been around since the late 1970s, said Matt Osman, a graduate student in the MIT-WHOI Joint Program and co-author of the study.

“We have had a sense that there’s been a great deal of melting in recent decades, but we previously had no basis for comparison with melt rates going further back in time,” he said. “By sampling ice, we were able to extend the satellite data by a factor of 10 and get a clearer picture of just how extremely unusual melting has been in recent decades compared to the past.”

Trusel said the new research provides evidence that the rapid melting observed in recent decades is highly unusual when put into a historical context.

“To be able to answer what might happen to Greenland next, we need to understand how Greenland has already responded to climate change,” he said. “What our ice cores show is that Greenland is now at a state where it’s much more sensitive to further increases in temperature than it was even 50 years ago.”

One noteworthy aspect of the findings, Das said, was how little additional warming it now takes to cause huge spikes in ice sheet melting.

“Even a very small change in temperature caused an exponential increase in melting in recent years,” she said. “So the ice sheet’s response to human-caused warming has been non-linear.”  Trusel concluded, “Warming means more today than it did in the past.”

Additional co-authors are: Matthew B. Osman, MIT/WHOI Joint Program in Oceanography; Matthew J. Evans, Wheaton College; Ben E. Smith, University of Washington; Xavier Fettweis, University of Leige; Joseph R. McConnell, Desert Research Institute; and Brice P. Y. Noël and and Michiel R. van den Broeke Utrecht University.

This research was funded by the US National Science Foundation, institutional support from Rowan University and Woods Hole Oceanographic Institution, the US Department of Defense, the Netherlands Organization for Scientific Research, the Netherlands Earth System Science Center, and the Belgian National Fund for Scientific Research.

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Link to paper (on and after Dec. 5, 2018): https://doi.org/10.1038/s41586-018-0752-4  

News media contacts:

WHOI Media Office- 508-289-3340, media@whoi.edu
Sarah Das, Ph.D., Woods Hole Oceanographic Institution (508) 289-2464 (office), sdas@whoi.edu https://www2.whoi.edu/staff/sdas/
Stephen Levine, News Officer, University Relations, Rowan University(856) 256-5443 (office), (856) 889-0491 (cell), Levines@Rowan.edu
Luke Trusel, Ph.D., School of Earth & Environment, Rowan University (856) 256 5262 (office), (508) 981-3073 (cell), trusel@rowan.edu, https://cryospherelab.org 

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education.  

DRI ice core data illustrates climate “teleconnection” between Earth’s poles during climate changes in the last Ice Age

DRI ice core data illustrates climate “teleconnection” between Earth’s poles during climate changes in the last Ice Age

Reno, Nev. (Nov. 28, 2018): This week, new research on historical climate changes in the Earth’s polar regions by an international team of scientists was published in the journal Nature. The study, titled “Abrupt Ice Age Shifts in Southern Westerlies and Antarctic Climate Forced from the North,” is underpinned by data provided by Joe McConnell, Ph.D., director of DRI’s Ultra-Trace Chemistry Laboratory in Reno, Nev.

The recently published study explains the interconnection between Arctic and Antarctic climates, tracing how strong currents in the North Atlantic during the Ice Age forced Southern Hemisphere climate on two different timescales: first, by rapidly warming Greenland and triggering immediate atmospheric changes in Antarctica due to shifting wind patterns, and second, by cooling the continent via colder ocean temperatures two centuries later. Researchers liken the atmospheric climate change in the North Atlantic to a “text message,” delivered immediately to the Southern Hemisphere, while the oceanic cooling is more like a “postcard,” not felt in Antarctica for another 200 years.

To identify this climate “teleconnection” between Earth’s poles, researchers relied on detailed chemical analyses of more than 1.5 km of Antarctic ice core, including more than 400,000 individual measurements, made in the Ultra-Trace Chemistry Laboratory using a unique continuous flow system and inductively coupled plasma mass spectrometry. Retrieved from the West Antarctic Ice Sheet (WAIS), this ice core sample, known as the WAIS Divide core, was collected by a team including DRI emeritus research professor Kendrick Taylor, Ph.D. Their original research into the connection between the Earth’s polar regions using the WAIS Divide core was first explained in Nature in 2015.

The full text of the study titled “Abrupt ice-age shifts in southern westerly winds and Antarctic climate forced from the north” is available in Naturehttps://www.nature.com/articles/s41586-018-0727-5. A full news release from Oregon State University is below.

(more…)

First non-polar historical iodine record shows impact of fossil fuel emissions

First non-polar historical iodine record shows impact of fossil fuel emissions

Reno, Nev. (Nov. 13, 2018): A new ice core record from the French Alps shows impacts of fossil fuel emissions in the form of a steep increase in iodine levels during the second half of the 20th century, according to a study released this week by an international team of scientists from the Université Grenoble Alpes-CNRS of France, the Desert Research Institute (DRI) in Reno, Nev., and the University of York in England.

“Model and laboratory studies had suggested that atmospheric iodine should have increased during recent decades as a result of increasing fossil fuel emissions but few long-term records of iodine existed with which to test these model findings, and none in Western Europe where modeled iodine increases were especially pronounced,” said French researcher and lead author Michel Legrand, Ph.D.

Iodine is an important nutrient for human health, key in the formation of thyroid hormones. It is present in ocean waters, and is released into the atmosphere when Iodide (I-) reacts with ozone (03) at the water’s surface. From the atmosphere, iodine is deposited onto Earth’s land surfaces, and absorbed by humans in the foods that we eat.

The new study, published in the Proceedings of the National Academy of Sciences, was initiated after scientists observed a three-fold increase in iodine between 1950 and the 1990s measured in an ice core from the Col du Dome region of France. The core was collected by French scientists and analyzed in 2017 in DRI’s Ultra Trace Ice Core Analysis Laboratory.

 

Researchers examine an ice core sample drilled from Mont Blanc.

Researchers examine an ice core sample drilled from Mont Blanc. Credit: B. Jourdain, L’Institut des Géosciences de l’Environnement.

Although previous modeling simulations had indicated a similar increase in global iodine emissions during the 20th century, this new record provides the first ice core iodine record from outside of the polar regions.

“Iodine has been measured previously in polar ice cores but changes there largely can be attributed to variations in sea ice,” said Joe McConnell, Ph.D., research professor of hydrology and head of DRI’s ice core laboratory. “These variations mask the larger scale trends linked to fossil fuel emissions and changes in ozone chemistry. Our new iodine record extends from 1890 to 2000 and is from the French Alps, a part of the world where there are no sea ice influences.”

As part of this study, more than 120 meters (nearly 400 feet) of ice core from the French Alps was analyzed for iodine and a broad range of chemical species by a group of DRI researchers that included McConnell, Monica Arienzo, Ph.D., Nathan Chellman, and Kelly Gleason, Ph.D., using DRI’s unique continuous analytical system.

The study team then analyzed the ice core record alongside modeling simulations to investigate past atmospheric iodine concentrations and changes in iodine deposition across Europe. According to their results, the observed tripling of iodine levels in the ice during the 1950s to 1990s were caused by increased iodine emissions from the ocean.

An ice core sample is processed in DRI’s Ultra-Trace Ice Core Laboratory in Reno, Nev.

An ice core sample is processed in DRI’s Ultra-Trace Ice Core Laboratory in Reno, Nev. Credit: Joe McConnell/DRI.

Ozone in the lower atmosphere acts as an air pollutant and greenhouse gas. Because iodine emissions from the ocean occur when iodine in the water reacts with ozone in the lower atmosphere, the study results indicate that increased ozone levels are increasing the availability of iodine in the atmosphere – and also that iodine is helping to destroy this “bad” ozone.

“Iodine’s role in human health has been recognized for some time – it is an essential part of our diets,” said Lucy Carpenter, Ph.D., Professor with University of York’s Department of Chemistry. “Its role in climate change and air pollution, however, has only been recognized recently and the impact of iodine in the atmosphere is not currently a feature of the climate or air quality models that predict future global environmental changes.”

According to the World Health Organization, iodine deficiency remains a significant health problem in parts of Europe, including France, Italy and certain regions of Spain – regions that now appear to have received a boost in iodine levels in recent years.

“The silver lining in the findings of this study is that the increase in human-caused pollution during the latter half of the 20th century may be leading to an increase in the availability of iodine as an essential nutrient,” Legrand said.

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To view the study, titled Alpine ice evidence of a three-fold increase in atmospheric iodine deposition since 1950 in Europe due to increasing oceanic emissions, published in the journal Proceedings of the National Academy of Sciences on 12 November 2018, please visit:  http://www.pnas.org/content/early/2018/11/07/1809867115

Samantha Martin from the University of York contributed to this release.

The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. Learn more at dri.edu, and connect with us on social media on Facebook, Instagram and Twitter

DRI ice core data provides insight into how dust and precipitation reach Earth’s poles

DRI ice core data provides insight into how dust and precipitation reach Earth’s poles

Above: A lone researcher is silhouetted by the summer sun, low in the Antarctic sky. Credit: Bradley Markle, UCSB.


Reno, Nev. (Sept. 20, 2018) – In September, new research by a team from the University of California, Santa Barbara, the University of Washington, Columbia University, and the Desert Research Institute (DRI) was published in the journal Nature Geoscience. The study, titled Concomitant variability in high-latitude aerosols, water isotopes and the hydrologic cycle, utilized data provided by Joe McConnell, Ph.D., director of DRI’s Ultra-Trace Chemistry Laboratory in Reno, Nev.

The study explains an observed connection between concentrations of aerosols (small atmospheric particles such as mineral dust and sea-salt) and the ratios of different isotopes of water (variant forms of H20 in which the atoms carry extra neutrons) found in Antarctic ice cores.

Aerosol measurements for this study, which consisted of more than 500,000 measurements of calcium and sodium in 2.1 kilometers (1.3 miles) of Antarctic ice, were made in the Ultra-Trace Chemistry Laboratory using a unique continuous flow system and inductively coupled plasma mass spectrometry. Parts of these aerosol records have been published previously, but they are published in full in the new study. The full news release from U.C. Santa Barbara is below.


Researcher on ice in Antarctica.

These shallow cores help us with the interpretation of the deep one,” explained UC Santa Barbara’s Bradley Markle. Credit: Bradley Markle, UCSB.

Dust, Rain and the Poles

Warmer climates will likely decrease the amount of airborne sediments reaching the poles

By Harrison Tasoff, University of California, Santa Barbara

Every year, the global climate transports billions of tons of dust around the world. These aerosols play a key role in many of Earth’s geological and biological cycles.

For instance, wind blows millions of tons of dust from the Sahara Desert across the Atlantic Ocean, where it fertilizes the Amazon Rainforest. The collective action of billions of trees pumping water from the ground then generates its own weather pattern, affecting the whole of South America.

When climate scientist Bradley Markle, at UC Santa Barbara’s Earth Research Institute, spotted a correlation between the ratios of heavy molecules and the concentration of particulate matter in the Antarctic ice cores he was studying, he immediately set out to uncover the deeper connection. His findings appear in the journal Nature Geoscience.

For decades scientists have been puzzled by the relationship between aerosol concentrations and the ratios of different molecules of water in ice cores, and Markle appears to have finally found the connection. His research increases our understanding of the processes at work in Earth’s atmosphere and could help to improve our climate models.

Markle focuses on understanding how climactic processes concentrate atoms of different weights in certain areas. Consider oxygen, for example. Every oxygen atom has eight positively charged protons. That’s what makes it oxygen. However, the number of neutrally charged neutrons it contains can vary from eight to 10. And the greater the number of neutrons, the heavier the isotope.

Water has one oxygen atom bonded to two hydrogen atoms, so water containing lighter isotopes, like 16O — which has eight neutrons — weighs less than water with heavier ones, like 18O — which has 10. Certain processes affect heavier molecules more than their lighter counterparts, leading to varying distributions of different weights across the globe. So even though 99.7 percent of oxygen on Earth is 16O, slight differences in the ratio between 16O and 18O provide scientists with valuable clues about the planet’s climate. In fact, measurements of these ratios in ice cores underlie our most detailed long records of Earth’s temperature history, Markle explained. They span hundreds of thousands of years before humans started measuring temperature directly.

Researchers examine the ice cores, which are backlit by the sun. Credit: Bradley Markle, UCSB.

Researchers examine the ice cores, which are backlit by the sun. Credit: Bradley Markle, UCSB.

Scientists noticed that ice layers with higher ratios of heavy isotopes also contained a greater concentration of trapped aerosols. “And it’s a very unique relationship, too,” Markle said. “It’s very clearly logarithmic … so it seems like it needs a strong, logarithmic process to account for it.

“The correlation between the thing that records the climate (the water isotope ratios) and these aerosols is extremely good,” he continued. “Better than you get in almost anything else in this field.”

Precipitation has the most influence on the percentage of heavy isotopes that make it to high latitudes, since heavier water molecules condense more readily compared to light ones, Markle explained. Warm air holds more moisture than cold air, so as it cools on its way toward the poles, the moisture condenses and preferentially loses the heavier molecules. If the poles become warmer, the air will not cool as much, so a greater number of heavy molecules will make it to higher latitudes. As a result, scientists associate low ratios of heavy isotopes with colder periods in Earth’s history.

Scientists suspected that these climatic conditions impacted the locations these aerosols came from, somehow effecting greater emissions during cooled periods than warm ones. However, years of research had yet to produce a model that fit the data. In addition, source variability is challenging to investigate because it requires looking at myriad factors in many different places. “People have investigated it, and they can’t get the sources to have such large changes in aerosol emissions,” Markle said.

Markle compared aerosol data from the Antarctic ice cores with similarly aged seafloor sediment from the oceans just below South America, which is the dominant source of the airborne dust found in Antarctica. He discovered that aerosol levels in the ocean sediment increased three- to six-fold during the last glacial maximum. However, concentrations in the ice cores soared to levels 20 to 100 times baseline rates. Clearly most of the change seen in the ice cores must be due to factors far from the source of the aerosols.

Then Markle recognized a similarity between the isotope ratios and the aerosol concentrations: The physics of moisture in the atmosphere is driving both of them.

A view of the Antarctic coast from the Southern Ocean. Credit: Bradley Markle, UCSB.

A view of the Antarctic coast from the Southern Ocean. Credit: Bradley Markle, UCSB.

Without aerosols, the world would have no rain. Water vapor needs a surface to condense, or form droplets. This could be a steamy shower window or a fleck of dust floating high in the clouds. In this way, precipitation washes the sky of aerosols. More precipitation between the source of the aerosols and the poles means lower concentrations of aerosols make it to the glaciers, and thus into the ice cores. And more precipitation also leads to lower ratios of heavy isotopes. Markle had discovered the connection.

What’s more, the scouring effect precipitation has on aerosols is exponential, meaning its influence increases the longer, and farther, the aerosols travel from their source. Precisely the sort of relationship Markle needed to match the data.

“This rainout theory ends up solving a whole bunch of things at once,” Markle said. It clarifies the correlation between aerosol concentrations and water isotopes, as well as the greater variability in aerosol levels at the poles than in locations closer to the source of the debris. The effect also explains why dust levels vary more than sea salt levels in the aerosol record: The ocean is closer to Antarctica than the source of dust, so precipitation has less impact on the amount of sea salt that makes it to the West Antarctic ice-sheet.

Markle is cautious about making predictions for our current climate change. “The effect that we saw in the ice cores was a really big effect, but it’s a big effect on multicentury, multimillennium time scales,” Markle said. Other sources of variability may be more prominent over shorter timeframes, he explained.

Nonetheless, warming temperatures would forecast decreasing concentrations of aerosols reaching the Arctic and Antarctic. Since aerosols reflect heat and sunlight, this could exacerbate warming trends over long periods of time. Changes in aerosol distribution could also affect the ocean, since they also contain nutrients and minerals vital to ocean’s food web.

Markle plans to leverage his newfound understanding of these relationships to investigate changes not only in the strength of hydrologic cycle but also in its spatial pattern. “Because the hydrologic cycle is tied to Earth’s temperature gradients, I think we can use these records to understand changes in polar amplification,” he explained. This is the phenomenon where the poles warm more than lower latitudes during climate change.

“This is a big deal in modern climate change,” he added, “and understanding how it has happened in the past would be extremely useful.”

This news release was originally published by the University of California, Santa Barbara. To view the original story, please visit:  http://www.news.ucsb.edu/2018/019185/dust-rain-and-poles

To view the study titled Concomitant variability in high-latitude aerosols, water isotopes and the hydrologic cycle, published in Nature Geoscience on 10 September 2018, please visit: https://www.nature.com/articles/s41561-018-0210-9

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

Low-severity wildfires impact soils more than previously believed

Low-severity wildfires impact soils more than previously believed

Above: In semi-arid ecosystems such as the Humboldt-Toiyabe National Forest near Las Vegas, which burned as part of the Carpenter 1 fire during July and August 2013, fuel is limited and fires tend to be short lived and low in peak temperature. New research shows that these fires are more harmful to soils than they initially appear. This photo was taken on January 6, 2015 – approximately 18 months after the wildfire. Credit: Teamrat Ghezzehei, UCM.


New research shows negative effects of fire on soil structure and organic matter

Las Vegas, NV (August 28, 2018): Low-severity wildland fires and prescribed burns have long been presumed by scientists and resource managers to be harmless to soils, but this may not be the case, new research shows.

According to two new studies by a team from the University of California, Merced (UCM) and the Desert Research Institute (DRI), low-severity burns – in which fire moves quickly and soil temperature does not exceed 250oC (482oF) – cause damage to soil structure and organic matter in ways that are not immediately apparent after a fire.

“When you have a high-severity fire, you burn off the organic matter from the soil and the impact is immediate,” said Teamrat Ghezzehei, Ph.D., principal investigator of the two studies and Associate Professor of Environmental Soil Physics at UCM. “In a low-severity fire, the organic matter doesn’t burn off, and there is no visible destruction right away. But the burning weakens the soil structure, and unless you come back at a later time and carefully look at the soil, you wouldn’t notice the damage.”

DRI researcher Markus Berli, Ph.D., Associate Research Professor of Environmental Science, became interested in studying this phenomenon while visiting a burned area near Ely, Nev. in 2009, where he made the unexpected observation that a prescribed, low-severity fire had resulted in soil structure damage in the burned area. He and several colleagues from DRI conducted a follow-up study on another controlled burn in the area, and found that soil structure that appeared to be fine immediately after a fire but deteriorated over the weeks and months that followed. Berli then teamed up with Ghezzehei and a team from UCM that included graduate student Mathew Jian, and Associate Professor Asmeret Asefaw Berhe, Ph.D., to further investigate.

Researcher examines soils in a burned area near Las Vegas.

Researcher Markus Berli from the Desert Research Institute examines the soils at a burned area in the Humboldt-Toiyabe National Forest near Las Vegas on January 6, 2015, approximately 18 months after the area burned in the Carpenter 1 fire of 2013. Credit: Teamrat Ghezzehei, UCM.

Soil consists of large and small mineral particles (gravel, sand, silt, and clay) which are bound together by organic matter, water and other materials to form aggregates. When soil aggregates are exposed to severe fires, the organic matter burns, altering the physical structure of the soil and increasing the risk of erosion in burned areas. In low-severity burn areas where organic matter doesn’t experience significant losses, the team wondered if the soil structure was being degraded by another process, such as by the boiling of water held within soil aggregates?

In a study published in AGU Geophysical Research Letters in May 2018, the UCM-DRI team investigated this question, using soil samples from an unburned forest area in Mariposa County, Calif. and from unburned shrubland in Clark County, Nev. to analyze the impacts of low-severity fires on soil structure. They heated soil aggregates to temperatures that simulated the conditions of a low-severity fire (175oC/347oF) over a 15-minute period, then looked for changes in the soil’s internal pore pressure and tensile strength (the force required to pull the aggregate apart).

During the experiment, they observed that pore pressure within the soil aggregates rose to a peak as water boiled and vaporized, then dropped as the bonds in the soil aggregates broke and vapor escaped. Tensile strength measurements showed that the wetter soil aggregates had been weakened more than drier soil samples during this process.

“Our results show that the heat produced by low-severity fires is actually enough to do damage to soil structure, and that the damage is worse if the soils are wet,” Berli explained. “This is important information for resource managers because it implies that prescribed burns and other fires that occur during wetter times of year may be more harmful to soils than fires that occur during dry times.”Next, the research team wondered what the impact of this structural degradation was on the organic matter that the soil structure normally protects. Soil organic matter consists primarily of microbes and decomposing plant tissue, and contributes to the overall stability and water-holding capacity of soils.

In a second study that was published in Frontiers in Environmental Science in late July, the UCM-DRI research team conducted simulated burn experiments to weaken the structure of the soil aggregates, and tested the soils for changes in quality and quantity of several types of organic matter over a 70-day period.

They found that heating of soils led to the release of organic carbon into the atmosphere as CO2 during the weeks and months after the fire, and again found that the highest levels of degradation occurred in soils that were moist. This loss of organic carbon is important for several reasons, Ghezzehei explained.

“The loss of organic matter from soil to the atmosphere directly contributes to climate change, because that carbon is released as CO2,” Ghezzehei said. “Organic matter that is lost due to fires is also the most important reserve of nutrients for soil micro-organisms, and it is the glue that holds soil aggregates together. Once you lose the structure, there are a lot of other things that happen. For example, infiltration becomes slower, you get more runoff, you have erosion.”

Researcher collects soil samples in burned area near Las Vegas.

Researcher Rose Shillito from DRI collects soil samples in a burned area in the Humboldt-Toiyabe National Forest near Las Vegas on January 6, 2015, approximately 18 months after the area burned in the Carpenter 1 fire of 2013. Credit: Teamrat Ghezzehei, UCM.

Although the research team’s findings showed several detrimental effects of fire on soils, low-severity wildfires and prescribed burns are known to benefit ecosystems in other ways — recycling nutrients back into the soil and getting rid of overgrown vegetation, for example. It is not yet clear whether the negative impacts on soil associated with these low-severity fires outweigh the positives, Berli says, but the team hopes that their research results will help to inform land managers as they manage wildfires and plan prescribed burns.

“There is very little fuel in arid and semi-arid areas, and thus fires tend to be short lived and relatively low in peak temperature,” Ghezzehei said. “In contrast to the hot fires and that burn for days and weeks that we see in the news, these seem to be benign and we usually treat them as such. Our work shows that low-severity fires are not as harmless as they may appear.”

The study, “Soil Structural Degradation During Low‐Severity Burns,” was published on May 31, 2018 in the journal AGU Geophysical Research Letters and is available here: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL078053.

The study, “Vulnerability of Physically Protected Soil Organic Carbon to Loss Under Low Severity Fires,” was published July 19, 2018 in the journal Frontiers in Environmental Science, and is available here: https://www.frontiersin.org/articles/10.3389/fenvs.2018.00066/full.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

Significant amount of cancer-causing chemicals stays in lungs during e-cigarette use, Nevada-based researchers find

Significant amount of cancer-causing chemicals stays in lungs during e-cigarette use, Nevada-based researchers find

Above: Dr. Vera Samburova works in the organic analytical lab at Desert Research Institute, in Reno, Nev., on Tuesday, Feb. 20, 2018.
Photo by Cathleen Allison/Nevada Momentum

Reno, NV (August 15, 2018) – E-cigarettes have become increasingly popular as a smoke-free alternative to conventional tobacco cigarettes, but the health effects of “vaping” on humans have been debated in the scientific and tobacco manufacturing communities. While aldehydes—chemicals like formaldehyde that are known to cause cancer in humans—have been identified in e-cigarette emissions by numerous studies, there has been little agreement about whether such toxins exist in large enough quantities to be harmful to users.

Now, a recently published pilot study by a team of researchers from the Desert Research Institute (DRI) and the University of Nevada, Reno shows that significant amounts of cancer-causing chemicals such as formaldehyde are absorbed by the respiratory tract during a typical vaping session, underscoring the potential health risks posed by vaping.

“Until now, the only research on the respiratory uptake of aldehydes during smoking has been done on conventional cigarette users,” said Vera Samburova, Ph.D., associate research professor in DRI’s Division of Atmospheric Sciences and lead author of the study. “Little is known about this process for e-cigarette use, and understanding the unique risks vaping poses to users is critical in determining toxicological significance.”

Samburova and fellow DRI research professor Andrey Khlystov, Ph.D., have been investigating the health risks associated with e-cigarettes for several years. In 2016, they published findings confirming that dangerous levels of aldehydes are formed during the chemical breakdown of flavored liquids in e-cigarettes and emitted in e-cigarette vapors.

In this study, Samburova and her team estimated e-cigarette users’ exposure to these hazardous chemicals by analyzing the breath of twelve users before and after vaping sessions using a method she and Khlystov have developed over the course of their work together. Through this process, they determined how much the concentration of aldehydes in the breath increased. Researchers then subtracted the concentration of chemicals in exhaled breath from the amount found in the vapors that come directly from the e-cigarette.

The difference, Samburova explains, is absorbed into the user’s lungs.

E-cigarettes in the Organic Analytical Lab

E-cigarettes in the Organic Analytical Lab at DRI.

“We found that the average concentration of aldehydes in the breath after vaping sessions was about ten and a half times higher than before vaping,” Samburova said. “Beyond that, we saw that the concentration of chemicals like formaldehyde in the breath after vaping was hundreds of times lower than what is found in the direct e-cigarette vapors, which suggests that a significant amount is being retained in the user’s respiratory tract.”

The research team took care to ensure that the test conditions of the study mirrored real-life vaping sessions as much as possible. Most participants used their own e-cigarette devices during the study, used e-liquid flavors that were familiar to them, and inhaled for the amount of time that they ordinarily would, which allowed the research team to understand how e-cigarettes are typically used by regular users. Because they tested “normal” vaping experiences, researchers confirmed that the high concentrations of aldehydes found in other studies aren’t limited to laboratory conditions.

“Our new pilot study underlines the potential health risk associated with the aldehydes generated by e-cigarettes,” said Samburova. “In the future, e-cigarette aldehyde exposure absolutely needs to be studied with a larger set of participants.”

The study, “Aldehydes in Exhaled Breath during E-Cigarette Vaping: Pilot Study Results,” was published on August 7th in the journal Toxics and is available here: https://www.mdpi.com/2305-6304/6/3/46/htm#app1-toxics-06-00046. DOI: 10.3390/toxics6030046

This research was independently funded by DRI and conducted in DRI’s Organic Analytical Laboratory located in Reno, Nevada. For more information about the Organic Analytical Lab, visit: https://www.dri.edu/oal-lab.

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The Desert Research Institute (DRI) is a recognized world leader in basic and applied interdisciplinary research. Committed to scientific excellence and integrity, DRI faculty, students, and staff have developed scientific knowledge and innovative technologies in research projects around the globe. Since 1959, DRI’s research has advanced scientific knowledge, supported Nevada’s diversifying economy, provided science-based educational opportunities, and informed policy makers, business leaders, and community members. With campuses in Reno and Las Vegas, DRI serves as the non-profit research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

Gault site research pushes back date of earliest North Americans

Gault site research pushes back date of earliest North Americans

Stone tool assemblage recovered from the Gault Site. Credit: Produced by N Velchoff, The Gault School of Archaeological Research.

Luminescence dating confirms human presence in North America prior to 16 thousand years ago, earlier than previously thought

July 20, 2018 (Reno, NV) – For decades, researchers believed the Western Hemisphere was settled by humans roughly 13,500 years ago, a theory based largely upon the widespread distribution of Clovis artifacts dated to that time. Clovis artifacts are distinctive prehistoric stone tools so named because they were initially found near Clovis, New Mexico, in the 1920s but have since been identified throughout North and South America.

In recent years, though, archaeological evidence has increasingly called into question the idea of “Clovis First.”Now, a study published by a teamincluding DRI’s Kathleen Rodrigues, Ph.D. student, and Amanda Keen-Zebert, Ph.D., associate research professorhas dated a significant assemblage of stone artifacts to 16-20,000 years of age, pushing back the timeline of the first human inhabitants of North America before Clovisby at least 2,500 years.

Significantly, this research identifies a previously unknown, early projectile point technology unrelated to Clovis, which suggests that Clovis technology spread across an already well-established, indigenous population.

These projectile points are unique. We haven’t found anything else like them,” said Tom Williams, Ph.D., Postdoctoral Research Associate in the Department of Anthropology at Texas State University and lead author of the study. “Combine that with the ages and the fact that it underlies a Clovis component, and the Gault site provides a fantastic opportunity to study the earliest human occupants in the Americas.”

The research team identified the artifacts at the Gault Site in Central Texas, an extensive archaeological site with evidence of continuous human occupationThe presence of Clovis technology at the site is well-documented, but excavations below the deposits containing Clovis artifacts revealed well-stratified sediments containing artifacts distinctly different from Clovis.

Diagram of soil layers identified at the Gault Site.

To determine the ages of these artifacts, Rodrigues, Keen-Zebert, and colleagues used a process called optically stimulated luminescence (OSL) dating on the sediments surrounding them. In OSL, researchers expose minerals that have long been buried under sediment layers to light or heat, which causes the minerals to release trapped potassium, uranium, and thorium electrons that have accumulated over time due to exposure to ambient, naturally occurring radiation.When the trapped electrons are released, they emit photons of light which can be measured to determine the amount of time that has elapsed since the materials were last exposed to heat or sunlight.

“The fluvial nature of the sediments deposited at the Gault Site have created a poor environment for preservation of organic materials, so radiocarbon dating has not been a useful technique to apply in this region,” said Kathleen Rodrigues, graduate research assistant in DRI’s Division of Earth and Ecosystem Sciences. “This made luminescence dating a natural choice for dating the archaeological materials here.  We are really pleased with the quality of the results that we have achieved.” 

The study was published on July 11th in the journal Science Advances and is available here: https://advances.sciencemag.org/content/4/7/eaar5954.

For more information on DRI’s optically stimulated luminescence dating capabilities, visit https://www.dri.edu/luminescence-lab

Jayme Blaschke of the Texas State University Office of Media Relations contributed to this release.

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

Lead pollution in Greenland ice shows rise and fall of ancient European civilizations

Lead pollution in Greenland ice shows rise and fall of ancient European civilizations

Dr. Monica Arienzo inspects an ice core sample in the ice core lab at the Desert Research Institute in Reno, Nev. Photo credit: DRI.

Reno, NV (May 14, 2018): To learn about the rise and fall of ancient European civilizations, researchers sometimes find clues in unlikely places: deep inside of the Greenland ice sheet, for example.

Thousands of years ago, during the height of the ancient Greek and Roman empires, lead emissions from sources such as the mining and smelting of lead-silver ores in Europe drifted with the winds over the ocean to Greenland – a distance of more than 2800 miles (4600 km) – and settled onto the ice. Year after year, as fallen snow added layers to the ice sheet, lead emissions were captured along with dust and other airborne particles and became part of the ice-core record that scientists use today to learn about conditions of the past.

In a new study published in PNAS, a team of scientists, archaeologists and economists from the Desert Research Institute (DRI), the University of Oxford, NILU – Norwegian Institute for Air Research and the University of Copenhagen used ice samples from the North Greenland Ice Core Project (NGRIP) to measure, date and analyze European lead emissions that were captured in Greenland ice between 1100 BC and AD 800. Their results provide new insight for historians about how European civilizations and their economies fared over time.

“Our record of sub-annually resolved, accurately dated measurements in the ice core starts in 1100 BC during the late Iron Age and extends through antiquity and late antiquity to the early Middle Ages in Europe – a period that included the rise and fall of the Greek and Roman civilizations,” said the study’s lead author Joe McConnell, Ph.D., Research Professor of Hydrology at DRI. “We found that lead pollution in Greenland very closely tracked known plagues, wars, social unrest and imperial expansions during European antiquity.”

Map showing location of NGRIP ice core.

Map showing location of NGRIP ice core in relation to Roman lead/silver mines. Credit: DRI.

A previous study from the mid-1990s examined lead levels in Greenland ice using only 18 measurements between 1100 BC and AD 800; the new study provides a much more complete record that included more than 21,000 precise lead and other chemical measurements to develop an accurately dated, continuous record for the same 1900-year period.

To determine the magnitude of European emissions from the lead pollution levels measured in the Greenland ice, the team used state-of-the-art atmospheric transport model simulations.

“We believe this is the first time such detailed modeling has been used to interpret an ice-core record of human-made pollution and identify the most likely source region of the pollution,” said co-author Andreas Stohl, Ph.D., Senior Scientist at NILU.

Most of the lead emissions from this time period are believed to have been linked to the production of silver, which was a key component of currency.

“Because most of the emissions during these periods resulted from mining and smelting of lead-silver ores, lead emissions can be seen as a proxy or indicator of overall economic activity,” McConnell explained.

Using their detailed ice-core chronology, the research team looked for linkages between lead emissions and significant historical events. Their results show that lead pollution emissions began to rise as early as 900 BC, as Phoenicians expanded their trading routes into the western Mediterranean. Lead emissions accelerated during a period of increased mining activity by the Carthaginians and Romans primarily in the Iberian Peninsula and reached a maximum under the Roman Empire.

Graph of European lead emissions.

Chronology of European lead emissions that were captured in Greenland ice between 1100 BC and AD 800 in relation to major historic events. Credit: DRI.

The team’s extensive measurements provide a different picture of ancient economic activity than previous research had provided. Some historians, for example, had argued that the sparse Greenland lead record provided evidence of better economic performance during the Roman Republic than during the Roman Empire.

According to the findings of this study, the highest sustained levels of lead pollution emissions coincided with the height of the Roman Empire during the 1st and 2nd centuries AD, a period of economic prosperity known as the Pax Romana. The record also shows that lead emissions were very low during the last 80 years of the Roman Republic, a period known as the Crisis of the Roman Republic.

“The nearly four-fold higher lead emissions during the first two centuries of the Roman Empire compared to the last decades of the Roman Republic indicate substantial economic growth under Imperial rule,” said coauthor Andrew Wilson, Professor of the Archaeology of the Roman Empire at Oxford.

The team also found that lead emissions rose and fell along with wars and political instability, particularly during the Roman Republic, and took sharp dives when two major plagues struck the Roman Empire in the 2nd and 3rd centuries. The first, called the Antonine Plague, was probably smallpox. The second, called the Plague of Cyprian, struck during a period of political instability called the third-century crisis.

“The great Antonine Plague struck the Roman Empire in AD 165 and lasted at least 15 years. The high lead emissions of the Pax Romana ended exactly at that time and didn’t recover until the early Middle Ages more than 500 years later,” Wilson explained.

The research team for this study included ice-core specialists, atmospheric scientists, archaeologists, and economic historians – an unusual combination of expertise.

“Working with such a diverse team was a unique experience in my career as a scientist,” McConnell said. “I think that our results show that there can be great value in collaborating across disciplines.”

Analysis and interpretation of archived NGRIP2 ice-core samples were supported by the John Fell Oxford University Press Research Fund and All Souls College, Oxford, as well as the Desert Research Institute.

Photo of the project team.

The project team included an interdisciplinary team of researchers, including (left to right) Dr. Audrey Yau, ice core specialist and former DRI post-doc; Dr. Monica Arienzo, ice core specialist, DRI; Elisabeth Thompson, doctoral student, Oxford University; Professor Andrew Wilson, historian, Oxford University; and Professor Joe McConnell, ice core specialist, DRI.

 

Ancient ‘quids’ reveal genetic information, clues into migration patterns of early Great Basin inhabitants

Ancient ‘quids’ reveal genetic information, clues into migration patterns of early Great Basin inhabitants

Above: Cave opening at the Mule Springs Rockshelter in southern Nevada’s Spring Mountain Range. Credit: Jeffrey Wedding, DRI.


 

Las Vegas, NV (April 24, 2018): If you want to know about your ancestors today, you can send a little saliva to a company where – for a fee – they will analyze your DNA and tell you where you come from. For scientists trying to find out about ancient peoples, however, the challenge is more complex.

Research published in the journal PLOS ONE by a team of archaeologists and microbiologists from Nevada’s Desert Research Institute (DRI) and Southern Illinois University Carbondale (SIU) showcases the use of modern research methods to uncover clues about the genetic ancestry of Native Americans who inhabited the Desert Southwest during the last thousand years.

“We were surprised by the consistency with which we were able to recover intact human DNA from a common type of plant-based artifact,” explained co-principal investigator Duane Moser, Ph.D., an associate research professor of microbiology at DRI and director of DRI’s Environmental Microbiology Laboratory.

During the Late Holocene Epoch, which began 12,000 to 11,500 years ago and continues through the present, occupants of the Mule Spring Rockshelter in the foothills of the Spring Mountains of southern Nevada commonly gathered agave and yucca plants for food. The artichoke-like hearts and inner leaves of the plants were roasted then chewed to consume the sweet fleshy pulp. This left wads of stringy fibers called ‘quids,’ which were spit out and left behind.

In the late 1960s, researchers from DRI and the University of Nevada, Las Vegas (UNLV) led by Richard Brooks, recovered thousands of quids at the rockshelter. Put into storage for half a century without any consideration for DNA preservation, a DRI-led research team decided to re-examine the quid specimens as possible repositories for ancient DNA.

“The quid’s coarse texture is excellent for capturing skin cells from the mouth, making them the equivalent of the modern-day cheek swab,” explained Susan Edwards, an associate research archaeologist at DRI and co-principal investigator who first thought of applying DNA extraction techniques to the quid samples.

A wad of stringy agave plant fibers commonly called ‘quids’.

A wad of stringy agave plant fibers commonly called ‘quids’. Credit: DRI

The research team used laboratory and computational resources at DRI’s Southern Nevada Science Center in Las Vegas, and later at SIU, to identify changes in the mitochondrial DNA sequences that are maintained in ancestrally related populations called haplogroups. These haplogroups can then be compared to Native American tribes and other ancient DNA lineages.

The study showed that the Mule Spring Rockshelter quid specimens ranged in age from about 350 to 980 years old. Because Mule Spring Rockshelter sits at a crossroads between the southern Great Basin, the Mojave Desert, and the Southwest Puebloan cultures, these results may provide a better timeline for an important but contentiously debated event in human history known as the Numic Spread.

Today’s Numic people contend they have always been here, a position some scientists readily support. However, some evidence suggests that Numic-speaking ancestors of contemporary native peoples spread from southern California throughout the Great Basin about 500 to 700 years ago; a date range which overlaps with the current study. Other studies suggest a much earlier arrival.

This research marks only the second time that scientists have been able to sequence human DNA from plant-based artifacts, expanding upon an approach utilized by Steven LeBlanc of Harvard University.

“Since these materials were also radiocarbon dated, in essence they provide a time-resolved hotel registry for this unique site over a period of hundreds of years,” added Moser.

As an added benefit of utilizing DNA from quid samples (rather than from more traditional sources such as bones or teeth), the research team found that they were able to obtain the information they needed while being respectful of cultural sensitivities.

“The distinct advantage of this genetic technique, is that it does not require the sampling of human remains” said Scott Hamilton-Brehm, lead author on the study and assistant professor of microbiology at SIU who completed his postdoctoral research at DRI.

In the future, the team hopes to continue this work by targeting additional quids from the Mule Spring Rockshelter collection, with the possibility of corroborating evidence of older dates for habitation of the site suggested by prior studies of more traditional cultural artifacts. Plans are in the works to perform similar studies on quids from other Great Basin sites to glean additional information about the movements of ancient peoples and utilize more powerful analytical approaches to obtain greater DNA sequence coverage than was obtained by this pilot study.

“We look forward to learning more about Native American presence in the Great Basin and Southwest area, and how the data compares over time,” added Lidia Hristova, a graduate of the UNLV Anthropology Program who conducted much of the hands-on DNA extraction from the samples while working as an undergraduate research assistant at DRI and studying at UNLV.

The full study, “Ancient human mitochondrial DNA and radiocarbon analysis of archived quids from the Mule Spring Rockshelter, Nevada, USA,” is available online from  PLOS ONE: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194223 

Mule Spring Rockshelter is a protected cultural resource located on BLM-managed lands. DRI access to the Mule Spring collection was granted under permit and loan agreement. 

Tim Crosby, Communications and Marketing Strategist at SIU Carbondale contributed to this press release. 

Additional photos available upon request.  

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit  www.dri.edu.

New research improves prospects for imperiled Devils Hole Pupfish in captivity

New research improves prospects for imperiled Devils Hole Pupfish in captivity

Above: Researchers Joshua Sackett (left) and Duane Moser (right) of DRI help National Park Service officials move scaffolding infrastructure during a routine sampling visit to Devils Hole on December 13, 2014. Credit: Jonathan Eisen.


DRI study finds key differences between artificial habitat and the real Devils Hole

Las Vegas, NV (Tuesday, March 20, 2018): In a first-of-its kind study of comparing the microbiology of Devils Hole with that of a constructed scale replica at the Ash Meadows Fish Conservation Facility (AMFCF), a team of scientists from the Desert Research Institute (DRI) in Las Vegas discovered key differences in nutrient levels and species composition that may be impacting the ability of the highly endangered Devils Hole Pupfish (Cyprinodon diabolis) to survive in captivity.

“We were interested in taking a closer look at the chemical and biological factors that control productivity at both sites,” said Duane Moser, Ph.D., an associate research professor of microbiology at DRI who has been involved with research at Devils Hole since 2008. “In studying both, we could gain some insights into how well the artificial refuge actually replicates Devils Hole, and in turn, offer recommendations for ways to make the refuge a better habitat for the pupfish.”

Devils Hole Pupfish (population 115 in autumn 2017) are an iridescent blue, one-inch-long pupfish. They are native only to Devils Hole, an isolated water-filled cavern of unknown depth located in a detached unit of Death Valley National Park within the Ash Meadows National Wildlife Refuge in Amargosa Valley, Nevada. Devils Hole is an extreme environment, with water temperatures and dissolved oxygen concentrations near their lethal limits for most fishes.

Since 2013, scientists have been trying to establish a backup population of these endangered fish in a constructed tank at the AMFCF, which is located a short distance west of Devils Hole. Although the facility was designed to match the climate, water chemistry and physical dimensions of an area of shallow shelf habitat in Devils Hole, the pupfish have had only limited success reproducing and surviving in this artificial environment.

In 2015, Moser and a team of researchers from DRI set out to learn if there were other factors that might be impacting the success of these fish. Their new study, published in the March edition of PLOS One, characterizes and compares water chemistry and microbial communities between Devils Hole and the AMFCF.

Although water temperature and dissolved oxygen at the AMFCF are intentionally maintained at values that are slightly lower and higher, respectively, from those of Devils Hole, this work shows that the nutrient balance between the two sites is also very different, with AMFCF being strongly nitrogen limited – about five times lower than that of Devils Hole.

In the microbial communities, which contribute to the distribution and availability of dissolved nutrients in the water and are also a food source for the pupfish, the research team discovered more than 2,000 microbial species from 44 distinct phyla present in the water at Devils Hole. They detected similar levels of species diversity at AMFCF, but found that different bacterial phyla were dominant at each site. These differences may relate to the observed differences in nitrogen concentrations.

“Nitrogen levels have an effect on the types of organisms that you’ll find, and the types of metabolisms that they have,” said Joshua Sackett, a graduate research assistant with the Desert Research Institute and doctoral student in the School of Life Sciences at the University of Nevada, Las Vegas. “We found a lot fewer of at least one major category of primary producers – the cyanobacteria – in the AMFCF compared to Devils Hole, and we think that’s due to differences in nutrient concentration.”

One of the strengths of the comparative power of this study is that the data from each site were gathered on the same day. This study highlights the potential importance of considering water chemistry and microbiology when constructing artificial fish habitats – and the team hopes that the information will provide a valuable contribution to the continued survival of the Devils Hole Pupfish in captivity.

“This work revealed very different microbial populations, which we infer might correspond to large differences in nutrient dynamics between the sites – especially in terms of nitrogen,” Moser said. “Consequently, some relatively modest tweaks in how the refuge is operated could potentially improve the prospects for continued survival of one of Earth’s most imperiled fishes.”

The full version of the study – A comparative study of prokaryotic diversity and physicochemical characteristics of Devils Hole and the Ash Meadows Fish Conservation Facility, a constructed analog – is available online: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194404

For more information about DRI, visit www.dri.edu

Photo caption: Researchers Joshua Sackett (left) and Duane Moser (right) of DRI help National Park Service officials move scaffolding infrastructure during a routine sampling visit to Devils Hole on December 13, 2014. Credit: Jonathan Eisen.

Additional photos are available upon request.

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

DRI Stories in the Snow Project collects over 400 images from local citizen scientists

DRI Stories in the Snow Project collects over 400 images from local citizen scientists

Above: Meghan Collins, Assistant Research Scientist of Environmental Science at DRI, demonstrates the use of a Stories in the Snow data collection kit. Credit DRI.


Detailed photographs help local scientists understand regional storms, collect weather data

Reno, NV (Wednesday, March 14, 2018): No two snow crystals are alike, an old saying goes – and this winter, students, and adults from across the Reno-Tahoe region are helping researchers from the Desert Research Institute (DRI) discover exactly what the unique shape of each freshly-fallen snowflake means for Nevada’s changing climate.

As part of a new citizen science project called “Stories in the Snow” (storiesinthesnow.org), DRI researchers are enlisting help from a quickly-growing network of students and volunteers in the Reno-Tahoe region to collect photographs of snow crystals each time it snows.

To date, the project has collected more than 400 photographs and data points from around the region, including more than 40 images from a recent storm that hit Reno-Tahoe in early March. In April, the research team will begin analysis of the data that has been collected this winter.

“To participate, all you need is a smartphone, a magnifying lens, and a flake of freshly fallen snow,” said Meghan Collins, education lead for the Stories in the Snow program and Assistant Research Scientist of Environmental Science at DRI. “We have partnered with 15 classes from schools in the local area and several educational non-profits. We are really excited to get students and community members involved in studying our snow and learning about climate science in our region.”

Project participants use a smartphone and data collection kit (available through the Stories in the Snow crowdfunding site) to capture up-close photographs of snowflakes, then submit the photos along with weather data on time, temperature and location to a DRI research team through the Citizen Science Lake Tahoe mobile app. The app, which was developed in partnership with the U.C. Davis Tahoe Environmental Research Center (TERC), is available for iPhone and Andriod operating systems. Following the Tom’s Shoes philanthropic model, each snowflake picture kit purchased through the project’s crowdfunding site provides a one-to-one matching donation of Stories in the Snow kits and training for local students.

By combining the photographs with common weather information on the time and location from which each snow crystal image was captured, DRI atmospheric research teams are learning about the temperature and water content of winter storm clouds. They are using the pictures and the weather data to better understand how snow storms in our region form and how warmer winters are impacting cloud physics and snow levels.

“We want to unravel what goes on in the clouds as a storm moves over the Sierra Crest and through our region,” said Frank McDonough, research lead for the Stories in the Snow project and associate research professor of atmospheric science at DRI. “The ice crystals tell us a lot about what happened during each snowflake’s journey – from how it first formed in the cloud all the way to how early it might melt and where it could land.”

From star-shaped “dendrites” too pointy “needles” and hexagonal “plates,” the shape and condition of each flake tells a unique story, McDonough explained. And if a flake appears covered in tiny, frozen droplets called “rime”, that is especially interesting to the research team – with possible implications for the aviation industry including research into airplane wing icing.

“If you see a snowflake with rime, you know that cloud had sub-freezing liquid water drops in it,” McDonough said. “Under those conditions, if an airplane flies through, the water droplets freeze on the airplane just like they freeze on the ice crystals. In extreme cases, the airplane can’t fly. Our main goal is to just understand clouds that exist below freezing, and what goes on in them when the water is present or absent.”

DRI initially piloted the Stories in the Snow program in several area schools during the winter of 2016-17 and launched a successful crowdfunding campaign to continue the project in October 2017. Now halfway through the 2017-18 season, Stories in the Snow is working in cooperation with teachers at ten local schools and three educational non-profits from the Reno-Tahoe region to enlist participation from students. They have also distributed more than 75 kits to other interested members of the public.

Data collected by the Stories in the Snow program is being used to support numerous projects, including improvements to climate and weather prediction models, validation of radar and satellite precipitation data, and data and insight for highway snow removal crews, avalanche forecasters, and water use planning groups. The research team also plans to make the data available to the public, so that any student or science-minded citizen can conduct their own investigations.

“If an amateur scientist wants to do a study on snowflakes, to see if they look different in March than in January, for example, we are excited to have them do that,” McDonough said. “We want the community to have access to the data. That’s the whole point with citizen science – giving people the opportunity to use these crystal images for their own projects, or just their own enjoyment.”

Stories in the Snow is supported during the 2017-2018 winter season by the Truckee-Tahoe Community Foundation and Nevada Space Grant.  For more information about the Stories in the Snow program, please visit http://storiesinthesnow.org, or follow along on Facebook (@storiesinthesnow) or Instagram (@storiesinthesnow). 

Additional photos available on Flickr: https://flic.kr/s/aHsmfQxuZL

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

Saving the Desert’s Upper Crust

To a casual observer, desert lands may appear a barren vista of sand and soil, sparsely dotted with shrubbery and cacti but, in reality, they are lush with microscopic plants: lichens, mosses, and cyanobacteria. There isn’t an inch of soil that is without these organisms.

“These organisms are a critical component of the desert ecosystem: they stabilize soils against erosion and provide essential nutrients to plants,” says NEXUS scientist Dr. Henry Sun, a research microbiologist at the Desert Research Institute (DRI).

These coverings-known as cryptogamic crusts-while providing essential ecosystem services, are also very fragile. Both the installation of solar farms and regular maintenance activities can disturb and remove this biological layer. “Such activities can destroy the crusts and result in increased dust emission,” Sun says. “And, once destroyed, they take decades to recover.”

Consequently, Sun and his graduate student, Lynda Burns, are trying to understand the impacts that large scale solar farms will have on this component of desert ecosystems and how to develop mitigation strategies to help prevent, or remediate any damage. “The goal of our research is to know the vulnerabilities of the organisms that build these protective crusts and to use the information to guide future restoration mitigation efforts in the context of solar plant impacts,” Sun says.

Banking Biology

The presence of these non-flowering plants is a key indicator of a healthy desert ecosystem. As well as forming a protective soil crust, and a barrier to erosion, they also provide nutrients to plants, mediate the transfer of water and provide a base for seed germination and plant growth.  In addition, the cyanobacteria can convert the nitrogen in the atmosphere into compounds that act as fertilizers for other plants, via a process called nitrogen fixation. “So you fix nitrogen using solar energy into a form that is available to plants,” Sun says.

Recognizing the importance of these crusts, and also their vulnerabilities, scientists have been investigating how to protect them. One suggested approach has been to harvest the crusts prior to a disturbance such as the installation of a solar farm, and save them. Once the construction is complete, the researchers’ suggestion is then to use the preserved crusts to inoculate the soil and aid in restoring the new crust.

The desert can prove a harsh environment for plants with temperatures and rainfall fluctuating between extremes. Also, a process called photochemical oxidation, facilitated by the sun’s ultraviolet rays can result in reactive oxygen species that are extremely damaging to life. “For this strategy to be effective, we need to know if the organisms lose vitality during storage, how long they would survive, and how to help them survive and thrive once they’ve been re-introduced to the desert habitat,” Sun says.

The scientific community does not yet know the answers to such questions and it was a knowledge gap that the NEXUS team set out to close. They began by collecting and saving the organisms in the soil crust and set about trying to understand how long those samples could survive and whether they could be successfully reintroduced to the desert environment. “There were two questions we’re trying to answer,” Sun says. “One, whether you can store the organisms and, two, when you reintroduce them what can we do to help them re-establish?”

Putting Crusts to the Test

In the lab, the scientists started their investigations by storing lichen samples from the Mojave Desert for different periods of time. In their natural habitat the lichens in the crusts alternate between drying out and hydration. During the desiccation process, they suffer from cellular damage but once they are hydrated repair and growth is possible. In their experiments, the researchers watered the stored samples and then monitored their recovery. “Healthy specimens become active within a minute of watering and compromised lichens go through a period of repair before they become productive,” Sun says. The researchers assumed that those lichens that showed no activity after 8 hours were dead.

Using this methodology, the scientists found that lichens can be stored dry at room temperature in ambient air for up to a year without any significant decline in vitality.  One-year old samples showed similar behavior to fresh samples: once they were given water they were ready to use light energy and photosynthesize.  Three and even ten-year-old samples were weaker and it would take them between 25 and 200 minutes to restore photosynthesis after the addition of water.

The scientists then attempted to determine how ultraviolet (UV) rays would impact the lichens when they were reintroduced back into the desert. The crust lichens protect themselves from UV light by synthesizing compounds that create a screen that blocks the harsh rays.  Even when the researchers put intense UV source as close as 25 centimeters away for one week the lichens suffered only minor damage. “It was well within their ability to repair,” Sun says. “This level of ionizing radiation resistance is unparalleled in the microbial world.”

The scientists did find, however, that the lichens were vulnerable to high concentrations of ozone. Fumigation in ozone for long periods caused photochemical oxidation, killing Collema, a cyanobacterial lichen, and severely damaging Placidium, a green algal lichen. Previous studies on the stress tolerance of crust-forming organisms considered only the impacts of UV radiation and desiccation. “Our work showed that photochemical oxidation presents a more severe stress than UV and desiccation,” Sun says. “And this has implications for crust storage and restoration.”

Given the evidence that the crust lichens are primarily vulnerable to oxidation, Sun recommends that the samples be stored in a non-oxidizing gas, such as nitrogen, instead of ambient atmosphere, to minimize oxidative stress.  In the field, amending the soil with antioxidants could protect the newly restored “seed” organisms from oxidation and thereby help them grow faster.  Both the ability of the organisms to be stored and their ability to survive typical desert conditions bodes well for the future, Sun says. “The research suggests that crust restoration is feasible and should be considered by land managers and solar companies,” Sun says.


This story was written by Jane Palmer and was originally published by the Solar-Energy-Water-Environment Nexus Project. For more information about the Nexus Project, visit: https://solarnexus.epscorspo.nevada.edu/

The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, visit www.dri.edu.

Scientists investigate northern Sierra Nevada snow droughts

Scientists investigate northern Sierra Nevada snow droughts

Above: From the east side of Washoe Lake, the view of Slide Mountain and Mount Rose on January 7, 2018, showed the effects of the ongoing snow drought. Warm wet and dry periods in November and a dry period in December created snow drought conditions throughout the region. Credit Benjamin Hatchett, DRI.


 

Reno, NV (Wednesday, January 17, 2018): The Lake Tahoe Basin and northern Sierra Nevada are currently experiencing a condition known as snow drought, according to new research and data from scientists at the Desert Research Institute (DRI). Snow droughts, or periods of below-normal snowpack, occur when abnormally warm storms or abnormally dry climate conditions prevent mountain snowpack from accumulating.

“As of early January, the snowpack in the Lake Tahoe Basin was only 28 percent of normal,” said Benjamin Hatchett, Ph.D., a postdoctoral researcher with DRI’s Division of Atmospheric Sciences. “We experienced warm wet and dry periods in November and a dry period in December that has created snow drought conditions throughout the region, followed by warm, rainy weather so far in January that has caused snowpack levels to decline further, especially at low elevation sites.”

Snow droughts have become increasingly common in the Sierra Nevada and Cascade mountains in recent years, as warming temperatures push snow lines higher up mountainsides and cause more precipitation to fall as rain.

Hatchett, an avid backcountry skier, began to notice the trend several years ago and recently published research outlining an approximately 1,200-foot rise in the winter snow levels over the last ten years across the northern Sierra Nevada.

Looking deeper into the rising snow levels and a general continued lack of snow in their local region, Hatchett and fellow DRI climate researcher Daniel McEvoy, Ph.D., an assistant research professor of climatology and regional climatologist at DRI’s Western Regional Climate Center (WRCC), sought to expand upon the little that is currently known about snow droughts and their impacts to local watersheds and economies.

In a new study recently published in the journal Earth Interactions, Hatchett and McEvoy explored the root causes of snow droughts in the northern Sierra Nevada, and investigate how snow droughts evolve throughout a winter season. To do this, they used hourly, daily and monthly data to analyze the progression of eight historic snow droughts that occurred in the northern Sierra Nevada between 1951 and 2017.

“We were interested in looking at the different pathways that can lead to a snow drought, and the different implications that each pathway has for mountain systems,” McEvoy explained.

Graph of the snow drought of 2017/2018.

The snow drought of 2017/2018 as observed at Fallen Leaf Lake, Calif. and the Central Sierra Snow Lab in Soda Springs, Calif. Map created by ClimateEngine.org – Powered by Google Earth Engine. Credit Benjamin Hatchett, DRI.

Previous research has used April 1st (the date that snowpack levels, measured as snow water equivalent or SWE, in the Sierra Nevada typically reach a maximum) as the primary date for calculating snow drought, and classified each snow drought as one of two types, warm or dry. “Warm snow drought” years were characterized by above-average levels of precipitation and below-average snow accumulation (SWE); “Dry snow drought” years were characterized by below-average levels of precipitation and below-average snow accumulation (SWE).

Hatchett and McEvoy’s work expanded upon these concepts by examining the progression of snow droughts throughout the entire winter season.

Their results illustrate that each snow drought originates and develops along a different timeline, with some beginning early in the season and some not appearing until later. Snow droughts often occurred as a result of frequent rain-on-snow events, low precipitation years, and persistent dry periods with warmer than normal temperatures. The severity of each snow drought changed throughout the season, and effects were different at different elevations.

“We learned that if you just look at snow levels on April 1st, you miss out on a lot of important information,” McEvoy said. “For example, if you are in a snow drought all winter long and come out of it right at the end due to a few big storms, there are probably implications to that.”

Sometimes, McEvoy explained, snow droughts were found to occur in years with above-average precipitation. For example, in 1997, a powerful atmospheric river storm event led to record-breaking flooding throughout the region – but much of the moisture arrived as rain rather than snow, with detrimental effects on the snowpack.

Climate change is likely to make snow drought an even more common phenomenon in the future, said Hatchett, as temperatures in the northern Sierra Nevada are expected to continue warming.

“There has always been an occasional snow drought year in the mountains, but that was typically the ‘dry’ type of snow drought caused by lack of precipitation,” Hatchett said. “As the climate grows warmer and more precipitation falls as rain instead of snow, we are seeing that we can have an average or above-average precipitation year and still have a well below-average snowpack.”

The implications of snow drought have not yet been studied extensively, but may include impacts to water resources, snowmelt runoff, flooding, soil moisture, tree mortality, ecological system health, fuel moisture levels that drive fire danger, human recreation, and much more. In regions such as the Lake Tahoe Basin, where mountain snowpack sustains wildlife, ecosystems, local economies, and provides crucial water resources to downstream communities throughout the year, the impacts of snow droughts could be enormous.

The last four winters, Hatchett and McEvoy noted, have all exhibited some degree of snow drought in the northern Sierra Nevada. Even the recent huge winter of 2016/17, which ended with far above-average snowpack levels (205% of the long-term median on April 1, 2017 in the Lake Tahoe Basin), began with a period of early-season snow drought during a dry November. This winter has been no exception, with snow drought taking hold over low elevation areas in November, and moving to higher elevation sites in December.

Only time will tell how the 2017/2018 winter season will end, but in the meantime, snow drought is affecting the region in ways that have not yet been fully quantified.

Hatchet and McEvoy hope that their research will prompt further investigations into the potentially devastating impacts of snow drought, and will help to inform regional climate adaptation planning efforts.

“We spend a lot of time going out and skiing, climbing, and hiking in the mountains, which is what inspired us to study these things,” Hatchett said. “We’re seeing and experiencing snow drought first-hand, and we have to quantify it and understand it because these are changing patterns on the landscape that will have massive implications for the mountain environments that we experience each day and the mountain communities that we live in.”

The full version of the study—“Exploring the Origins of snow drought in the northern Sierra Nevada, California”—is available online at –http://journals.ametsoc.org/doi/10.1175/EI-D-17-0027.1

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

Climate Engine offers unprecedented access to Earth image datasets

Climate Engine offers unprecedented access to Earth image datasets

Reno, NV (Thursday, December 7, 2017): Working with large environmental datasets is a complex and time-consuming endeavor, often requiring huge amounts of data storage, specialized high-performance computers and technical knowledge. Climate Engine (ClimateEngine.org), a new, free web-based application created by a team of scientists at the Desert Research Institute (DRI), University of Idaho, and Google is aiming to change all of that.

New research published and featured on the cover of the November issue of the Bulletin of the American Meteorological Society (BAMS) outlines how Climate Engine improves the accessibility of climate and weather data by allowing users to create on-demand maps or graphs of various earth observation datasets using a standard web browser. Datasets are stored and processed in the cloud on the Google Earth Engine platform, eliminating the need for users to download, store and process large data files on their computers.

Climate Engine provides access to a variety of geospatial datasets that track vegetation, snow and water across the planet, as well as climate datasets that track temperature, precipitation and winds.

One of the web application’s greatest strengths, according to Dr. Justin Huntington, co-principal investigator of the Climate Engine project and associate research professor of hydrology at DRI, lies in the application’s ability to quickly and easily pair satellite imagery with different climate variables.

“We can process field-scale Landsat satellite imagery like we’ve never been able to before,” Huntington said. “For example, we can look at over 30 years of vegetation changes in a certain area and then pair those changes with the same historical record of climate, all within one platform, in a matter of seconds.”

In the paper Climate Engine: Cloud Computing and Visualization of Climate and Remote Sensing Data for Advanced Natural Resource Monitoring and Process Understanding, the authors describe the development, design and potential uses for this tool. The paper highlights various case studies related to drought, wildfire and agriculture, which each provide examples of how Climate Engine can be used to generate on-demand maps and time-series analyses of different conditions and extreme events.

The authors outline the capability of this cutting-edge tool to analyze temperature change in the Arctic, evaluate vegetation stress during a historic drought in the Great Plains, map fire danger and burned acreage in Idaho, monitor groundwater-dependent ecosystems in Nevada, and support famine early-warning efforts in Ethiopia.

Because Climate Engine is free and requires no specialized software to use, Huntington and his colleagues hope that it will be useful to researchers and decision-makers around the world.

“Our work allows decision makers unprecedented access to analyzing big data related to environmental monitoring on their desktops and tablets without needing a supercomputer by using cloud computing resources provided by Google,” said John Abatzoglou, co-principle investigator of Climate Engine and associate professor of geography at the University of Idaho. “The ability to analyze such data in real time will help fill an information void and improve our ability to sustain our environmental resources including water.”

After using the web application to create a map or graph, results can be downloaded or shared in common file formats, saving users hours of time that was once spent downloading and processing large data archives.

“That’s the beauty of Climate Engine,” Huntington said. “Instead of downloading archives to get to the answer, you can just download the answer.”

Climate Engine was originally unveiled at the White House Water Summit in 2016. In the time since the product launched, the web application has been used by more than 8,000 unique visitors across the globe.

Recently, Climate Engine team members Huntington and Dr. Katherine Hegewisch of the University of Idaho presented a talk at the Famine Early Warning System (FEWS) science meeting in Washington D.C., and Hegewisch hosted a workshop for African FEWS field scientists.

Climate Engine will also be on display at the upcoming American Geophysical Union Annual Fall Meeting in New Orleans. The event is the largest and preeminent Earth and space science meeting in the world.

In the future, the Climate Engine team plans to continue adding new datasets such as sea surface temperature and European satellite data. They are also planning to add agency-specific spatial averaging domains, such as agency management boundaries and crop zones, and also hope to continue expanding their education and outreach efforts.

The idea behind Climate Engine, says Huntington, is to make large datasets available to researchers, decision-makers, journalists, farmers, or anyone else who might benefit from the information – and in an easy-to-use, approachable and simple format.

Climate Engine was primarily funded by Google and federal programs of the National Integrated Drought Information System, Famine Early Warning System Network, U.S. Geological Survey’s Landsat Science Team, and Bureau of Land Management’s Nevada State Office.

For more information and use the Climate Engine web application visit – ClimateEngine.org

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, UI serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, a research and Extension center in Twin Falls, plus Extension offices in 42 counties. Home to more than 11,000 students statewide, UI is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. UI competes in the Big Sky Conference and Sun Belt Conference. Learn more at www.uidaho.edu.

Massive Antarctic Volcanic Eruptions Linked to Abrupt Southern Hemisphere Climate Changes Near the End of the Last Ice Age

Massive Antarctic Volcanic Eruptions Linked to Abrupt Southern Hemisphere Climate Changes Near the End of the Last Ice Age

Above: A 15-meter pan-sharpened Landsat 8 image of the Mount Takahe volcano rising more than 2,000 meters (1.2 miles) above the surrounding West Antarctic ice sheet in Marie Byrd Land, West Antarctica. Credit: Landsat Image Mosaic of Antarctica (LIMA). USGS and NASA, LIMA Viewer, https://lima.gsfc.nasa.gov/. Image Date: March 4, 2015


New findings explain synchronous deglaciation that occurred 17,700 Years Ago

Reno, NV (Sept. 5, 2017) – New findings published today in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) by Desert Research Institute (DRI) Professor Joseph R. McConnell, Ph.D., and colleagues document a 192-year series of volcanic eruptions in Antarctica that coincided with accelerated deglaciation about 17,700 years ago.

“Detailed chemical measurements in Antarctic ice cores show that massive, halogen-rich eruptions from the West Antarctic Mt. Takahe volcano coincided exactly with the onset of the most rapid, widespread climate change in the Southern Hemisphere during the end of the last ice age and the start of increasing global greenhouse gas concentrations,” according to McConnell, who leads DRI’s ultra-trace chemical ice core analytical laboratory.

Climate changes that began ~17,700 years ago included a sudden poleward shift in westerly winds encircling Antarctica with corresponding changes in sea ice extent, ocean circulation, and ventilation of the deep ocean. Evidence of these changes is found in many parts of the Southern Hemisphere and in different paleoclimate archives, but what prompted these changes has remained largely unexplained.

“We know that rapid climate change at this time was primed by changes in solar insolation and the Northern Hemisphere ice sheets,” explained McConnell. “Glacial and interglacial cycles are driven by the sun and Earth orbital parameters that impact solar insolation (intensity of the sun’s rays) as well as by changes in the continental ice sheets and greenhouse gas concentrations.”

“We postulate that these halogen-rich eruptions created a stratospheric ozone hole over Antarctica that, analogous to the modern ozone hole, led to large-scale changes in atmospheric circulation and hydroclimate throughout the Southern Hemisphere,” he added. “Although the climate system already was primed for the switch, we argue that these changes initiated the shift from a largely glacial to a largely interglacial climate state. The probability that this was just a coincidence is negligible.”

Furthermore, the fallout from these eruptions – containing elevated levels of hydrofluoric acid and toxic heavy metals – extended at least 2,800 kilometers from Mt. Takahe and likely reached southern South America.

Monica Arienzo works with an ice core sample at DRI.

Monica Arienzo, Ph.D., an assistant research professor of hydrology at DRI, loads an 18,000-year-old sample of the WAIS Divide ice core for continuous chemical analysis using DRI’s ultra-trace ice core analytical system in Reno, Nevada. Credit: DRI Professor Joseph R. McConnell, Ph.D.

How Were These Massive Antarctic Volcanic Eruptions Discovered and Verified?

McConnell’s ice core laboratory enables high-resolution measurements of ice cores extracted from remote regions of the Earth, such as Greenland and Antarctica. One such ice core, known as the West Antarctic Ice Sheet Divide (WAIS Divide) core was drilled to a depth of more than two miles (3,405 meters), and much of it was analyzed in the DRI Ultra-Trace Laboratory for more than 30 different elements and chemical species.

Additional analyses and modeling studies critical to support the authors’ findings were made by collaborating institutions around the U.S. and world.

“These precise, high-resolution records illustrate that the chemical anomaly observed in the WAIS Divide ice core was the result of a series of eruptions of Mt. Takahe located 350 kilometers to the north,” explained Monica Arienzo, Ph.D., an assistant research professor of hydrology at DRI who runs the mass spectrometers that enable measurement of these elements to as low as parts per quadrillion (the equivalent of 1 gram in 1,000,000,000,000,000 grams).

“No other such long-lasting record was found in the 68,000-year WAIS Divide record,” notes Michael Sigl, Ph.D., who first observed the anomaly during chemical analysis of the core. “Imagine the environmental, societal, and economic impacts if a series of modern explosive eruptions persisted for four or five generations in the lower latitudes or in the Northern Hemisphere where most of us live!”

Discovery of this unique event in the WAIS Divide record was not the first indication of a chemical anomaly occurring ~17,700 years ago.

“The anomaly was detected in much more limited measurements of the Byrd ice core in the 1990s,” notes McConnell, “but exactly what it was or what created it wasn’t clear. Most previous Antarctic ice core records have not included many of the elements and chemical species that we study, such as heavy metals and rare earth elements, that characterize the anomaly – so in many ways these other studies were blind to the Mt. Takahe event.”

DRI’s initial findings were confirmed by analysis of replicate samples from WAIS Divide, producing nearly identical results.

“We also found the chemical anomaly in ice from two other Antarctic ice cores including archived samples from the Byrd Core available from the University of Copenhagen and ice from Taylor Glacier in the Antarctic Dry Valleys,” said Nathan Chellman, a graduate student working in McConnell’s laboratory.

Extraction of the WAIS-Divide ice core and analysis in DRI’s laboratory were funded by the U.S. National Science Foundation (NSF).

“The WAIS Divide ice core allows us to identify each of the past 30,000 years of snowfall in individual layers of ice, thus enabling detailed examination of conditions during deglaciation,” said Paul Cutler, NSF Polar Programs’ glaciology program manager. “The value of the WAIS Divide core as a high-resolution climate record is clear in these latest results and is another reward for the eight-year effort to obtain it.”

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.  

Black Carbon Emissions from Ancient Wildfires Linked to Historical Climate Conditions

Black Carbon Emissions from Ancient Wildfires Linked to Historical Climate Conditions

Monica Arienzo, PhD, assistant research professor of hydrology at DRI, demonstrates part of the black carbon analysis process in the clean room of DRI’s Ice Core Laboratory. Credit DRI.


DRI-led research team publishes longest ice core black carbon record to date

Reno, NV (Aug. 10, 2017): Smoky skies and burnt landscapes are the easily recognizable, local and immediate impacts of large wildfires. Long after these fires are gone, their emissions are cataloged and stored forever in ice covering the Earth’s polar regions.

New research, led by a team at the Desert Research Institute (DRI) in Reno, Nevada, has revealed that Earth’s ancient climate conditions affected large regional scale wildfires.

The new study identifies a link between the concentration of wildfire black carbon (BC) emissions —a type of biomass-burning aerosol particle commonly known as soot—found in Antarctic ice cores and climate conditions in the Southern Hemisphere during the mid-Holocene, about 6,000 years ago.

Led by Monica Arienzo, PhD, an assistant research professor of hydrology at DRI, a team of international researchers used DRI’s unique ultra-trace ice core analytical laboratory to measure BC concentrations in two Antarctic ice cores, ice that contains traces of compounds present in the atmosphere at the time the snow fell. This method allowed researchers to make comparisons to other records, such as lake and marine sediment cores, and develop a high-resolution record of biomass-burning emissions in the Southern Hemisphere from 14 to 2.5 thousand years before present day.

“This is the longest ice core black carbon record published to date,” Arienzo said, “and it tells us a fascinating story about wildfire.”

The new ice core record illustrates that, during the mid-Holocene, decreases in precipitation and soil moisture coupled with increases in temperature and fire season length in regions of South America were mirrored by increased concentrations of BC in Antarctic ice.

“Our analysis gives us a sense of what climate-fire relationships were like before significant human-caused changes to the climate,” explained Joe McConnell, PhD, a study co-author and research professor of hydrology at DRI. “Knowing what climate-fire relationships were like in the past will help scientists make more accurate climate models because they can account for BC contributions from wildfires in addition to those from human sources.”

BC acts as an agent of climate forcing, a process which occurs in the atmosphere when the amount of incoming energy is greater than the amount of outgoing energy, “forcing” the planet to adjust by releasing energy as heat and warming up. This is a natural process, catalyzed by events such as large volcanic eruptions and changes in the sun’s energy output; however, human-caused climate forcing in the form of BC emissions, has increased dramatically since the Industrial Revolution and now is a significant climate forcing agent, second only to carbon dioxide (CO2).

BC also impacts ice sheet albedo, the reflectivity of a surface. Ice and snow have a high albedo because they are very white and reflect much of the sun’s energy. This reflectivity keeps the snow and ice cold and delays melting. Conversely, snow and ice with BC deposits have a lower albedo, causing increased absorption of energy into the snow and ice and more rapid melting.

“Recent precipitation models indicate vast regional changes in rainfall in the Southern Hemisphere in the future,” Arienzo added. “Our findings indicate that such rainfall changes may be accompanied by changes in Southern Hemisphere wildfires. Given that BC emissions from human sources are predicted to increase, our findings are an important factor for climate predictions involving BC impacts.”

The full version of the study—“Holocene black carbon in Antarctica paralleled Southern Hemisphere climate”—is available online at – http://onlinelibrary.wiley.com/doi/10.1002/2017JD026599/full

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.

Source of Arctic Mercury Pollution Identified in New Study

Source of Arctic Mercury Pollution Identified in New Study

Researchers monitored mercury levels at Toolik Field Station, northern Alaska, in part, with this meteorological tower (foreground). Credit: Daniel Oberist, DRI.


DRI research team part of international effort to understand global impact

Reno, Nev. (July 14, 2017): Vast amounts of toxic mercury are accumulating in the Arctic tundra, threatening the health and well-being of people, wildlife and waterways, according to a new study published this month by an international team of scientists investigating the source of the pollution.

Led by Prof. Daniel Obrist, chairman of UMass Lowell’s Department of Environmental, Earth and Atmospheric Sciences, an atmospheric chemist and former lead of the Desert Research Institute’s (DRI) Mercury Analytical Lab, the study found that airborne mercury is gathering in the Arctic tundra, where it gets deposited in the soil and ultimately runs off into waters. Scientists have long reported high levels of mercury pollution in the Arctic.

The new research identifies gaseous mercury as its major source and sheds light on how the element gets there.

“Now we understand how such a remote site is so exposed to mercury,” Obrist said. Although the study did not examine the potential impact of global warming, if climate change continues unchecked, it could destabilize these mercury deposits in tundra soils and allow large amounts of the element to find its way into Arctic waters, he added.

Obrist and his colleagues – including students and researchers from DRI – recently completed two years of field research in the tundra, tracking the origin and path of mercury pollution. Working from an observation site in Alaska north of Brooks Range, he and an international group of scientists identified that gaseous mercury in the atmosphere is the source of 70 percent of the pollutant that finds its way into the tundra soil. In contrast, airborne mercury that is deposited on the ground through rain or snow – a more frequent focus of other studies – accounts for just 2 percent of the mercury deposits in the region, Obrist’s team found.

The new research is the most comprehensive investigation on how mercury is deposited in the Arctic. The full results of the study, which was supported by the National Science Foundation, appear in the July 13 edition of the prestigious academic journal Nature.

Mercury is a harmful pollutant, threatening fish, birds and mammals across the globe. The dominant source of mercury pollution in the atmosphere is hundreds of tons of the element that are emitted each year through the burning of coal, mining and other industrial processes across the globe.

This gaseous mercury is lofted to the Arctic, where it is absorbed by plants in a process similar to how they take up carbon dioxide. Then, the mercury is deposited in the soil when the plants shed leaves or die. As a result, the tundra is a significant repository for atmospheric mercury being emitted by industrialized regions of the world.

“This mercury from the tundra soil explains half to two-thirds of the total mercury input into the Arctic Ocean,” Obrist said, adding that scientists had previously estimated mercury runoff from tundra soil supplies 50 to 85 tons of the heavy metal to Arctic waters each year.

Exposure to high levels of mercury over long periods can lead to neurological and cardiovascular problems. The results are being felt by Arctic people and wildlife.

“Mercury has high exposure levels in northern wildlife, such as beluga whales, polar bears, seals, fish, eagles and other birds,” Obrist said. “It also affects human populations, particularly the Inuit, who rely on traditional hunting and fishing.”

Obrist will present the team’s research at the International Conference on Mercury as a Global Pollutant, which will be held Sunday, July 16 through Friday, July 21 in Providence, R.I. The event is the largest scientific conference on mercury pollution, involving nearly 1,000 participants from research institutions, governments and other agencies.

Obrist hopes to continue to investigate whether gaseous mercury is also a dominant source of pollution in other remote lands. Scientists, regulators and policymakers need a better understanding of how the uptake of gaseous mercury in plants and soils is affecting the environment, including the world’s forests, he said.

The research findings underscore the importance of the Minamata Convention on Mercury, the first global treaty that aims to protect human health and the environment from the element’s adverse effects, Obrist said. Signed by the United States and more than 120 other countries, the pact will take effect next month, with the goal of reducing mercury emissions caused by industrialization and other human activities.

Other contributors to the study include scientists from the University of Colorado; Gas Technology Institute in Des Plaines, Ill.; Desert Research Institute in Reno, Nev.; Sorbonne University in Paris, France; and University of Toulouse in Toulouse, France. Additional support for the research was provided by the U.S. Department of Energy, a Marie Sklodowska-Curie grant and funding from the European Research Council and the French National Centre for Scientific Research.

Contributors to this news release included Nancy Cicco, associate director of media relations; and Edwin l. Aguirre, senior science and technology writer/editor, University of Massachusetts Lowell.

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UMass Lowell is a national research university located on a high-energy campus in the heart of a global community. The university offers its more than 17,750 students bachelor’s, master’s and doctoral degrees in business, education, engineering, fine arts, health, humanities, sciences and social sciences. UMass Lowell delivers high-quality educational programs, vigorous hands-on learning and personal attention from leading faculty and staff, all of which prepare graduates to be ready for work, for life and for all the world offers. http://www.uml.edu

The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu

DRI Researchers Identify Connection Between Atmospheric River Events and Avalanche Fatalities in Western United States

RENO, Nev. (July 14, 2017) – Recently published research led by atmospheric scientists at the Desert Research Institute (DRI) demonstrates a connection between the occurrence of atmospheric river (AR) events and avalanche fatalities in the West.

Published in the May issue of the Journal of Hydrometeorology, the pilot study assessed avalanche reports, weather station data, and a catalog of AR data from a previous study to determine that AR conditions were present for 105 unique avalanches between 1998 and 2014, resulting in 123 fatalities (31 percent of all western avalanche fatalities during this time frame).

Atmospheric Rivers, as described by the National Oceanic and Atmospheric Administration (NOAA), are “relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics.”

When ARs make landfall on the West Coast of the US they release water vapor as rain or snow, supplying 30 to 50 percent of annual precipitation in the West and contributing to cool season (November to April) extreme weather events and flooding.

Researchers conclude that the intense precipitation associated with AR events is paralleled by an increase in avalanche fatalities. Coastal regions experience the highest percentage of avalanche fatalities during AR conditions; however, the ratio of avalanche deaths during AR conditions to the total number of AR days is actually higher further inland, in states like Colorado and Utah.

“Although ARs are less frequent in inland locations, they have relatively more important roles in intermountain and continental regions where snowpacks are characteristically weaker and less capable of supporting heavy rain or snowfall,” explained Benjamin Hatchett, a postdoctoral fellow of meteorology at DRI and lead author on the study.

“This means that avalanche forecasters, ski resort employees, backcountry skiers, and emergency managers who have an increased awareness of forecasted AR conditions can potentially reduce exposure to resultant avalanche hazards, particularly if snowpack conditions already indicate weakness,” he added.

The study also reports that shallow snowpacks weakened by persistent cold and dry weather can produce deadly and widespread avalanche cycles when combined with AR conditions. Climate projections indicate that this combination is likely to become more frequent in the mid- to late- 21st century, which could create significant avalanche risk to winter backcountry enthusiasts in the West.

“With increasing numbers of recreational backcountry users and changing mountain snowpack conditions, we might expect the future to be characterized by enhanced exposure to avalanche hazard throughout the western United States,” Hatchett said. “Our results provide motivation to further increase public awareness about avalanche threats during AR events.”

Including integrated vapor transport (IVT) forecasting tools in analyses of avalanche danger, researchers suggest, could potentially allow experts to increase the accuracy of avalanche forecasts when AR conditions are present. These tools can identify structure and movement of ARs when they make landfall, and also model how ARs move inland through gaps in mountainous terrain and cause heavy precipitation further inland.

“Our study provides motivation for additional examinations of avalanche data and meteorological conditions,” Hatchett said. “Our team recommends that following all, but especially fatal, avalanches, as much detailed information should be recorded as possible so that the field can continue to learn about the relationship between atmospheric river events and avalanches.”

The full version of the study – “Avalanche Fatalities during Atmospheric River Events in the Western United States” – is available online at the link below. http://journals.ametsoc.org/doi/full/10.1175/JHM-D-16-0219.1

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The Desert Research Institute (DRI) is a recognized world leader in investigating the effects of natural and human-induced environmental change and advancing technologies aimed at assessing a changing planet. For more than 50 years DRI research faculty, students, and staff have applied scientific understanding to support the effective management of natural resources while meeting Nevada’s needs for economic diversification and science-based educational opportunities. With campuses in Reno and Las Vegas, DRI serves as the non-profit environmental research arm of the Nevada System of Higher Education. For more information, please visit www.dri.edu.