|Affiliation(s)||PI||Project period||Funded by|
|DAS||Gillies, John A||04/01/2007 - 03/31/2011||National Science Foundation|
This research will quantify the spatial and temporal patterns of aeolian sediment transport in the McMurdo Dry Valleys of Antarctica during both the winter and summer periods. Winter period process measurements, which have never been undertaken, are essential for determining the frequency and magnitude of transport events to determine if present aeolian transport rates are sufficient to explain the active development of bedforms, landforms and deposits present in the Dry Valleys or whether these features are relict, having been formed during a paleoclimatic regime that was more conducive to their formation. This project will also provide important information critical to our understanding of the ecology of the Dry Valleys. The role of wind in the distribution of nutrients and biota has been shown to be an important distribution mechanism, but the frequency and magnitude of wind driven sediment events and the accompanying transport of biologically important (nutrients) or biologically active components (e.g., nematodes in an anhydrobiotic state) remains highly uncertain. The proposed work will meet this overall objective through two linked research activities: (1) a process-based study using dynamic and time-integrated measurements of aeolian sand transport to characterize the temporal (i.e., seasonal) behavior, frequency, and magnitude of sand transport events for 3.5 years (4 summer periods, 3 winter periods) at six sites within the McMurdo Dry Valley system (Taylor, Wright, and Victoria Valleys) where aeolian activity has been previously observed. As part of their thesis research, one graduate student will focus their efforts on aspects of the sand transport system. Two of the six proposed sites are within the McMurdo LTER (Lake Fryxell and Lake Hoare nematode sites) and will serve to establish bounds there on sediment distribution processes by wind. LTER scientists will be supplied with collected sediments, which they can use to evaluate its inorganic and organic nutrient content, and potentially biotic content as well. We propose to combine our process measurements with detailed surveying of the aeolian megaripples found in the Wright Valley, which represent an end-member bedform created by the aeolian sediment transport system. By focusing on these bedforms we can ascertain whether the extreme wind events associated with present day katabatic flows are sufficient to mobilize and sustain these forms. The second student will focus their research on the megaripples, integrating the process data with morphometric and survey data to evaluate whether current formation processes can explain the presence of this form. The bedform activity of the megaripples will be assessed by the repeated mapping of the form as well as through the use of emplaced tracer particles to determine rates of movement of individual particles. Observed movement of tracer particles will be related to the measured sediment transport frequency and magnitude data, which will be taken at this site similarly to the other proposed measurement sites. The broader impacts of this work include the support of graduate students and their integration into a strong internationally recognized group of scientists working on aeolian processes. Our proposed program will actively bring our research to students at all levels, and in particular, young women, encouraging and fostering their participation in science. The educational component of this proposed research will be supported through our established NSF-funded DRI outreach program (N-STEP) with Co-PI Gillies continuing to give presentations on his research to K-12 students at Nevada public schools. Nickling will also continue his active involvement with high schools in Canada through established outreach programs at the University of Guelph as well as his continued public presentations to community and service groups. Co-PI Lancaster has been involved in efforts to promote wider knowledge and understanding of desert geomorphology and aeolian processes via documentary films and television programs. The proposed research also has importance beyond the understanding of aeolian processes in the Dry Valleys. The Dry Valley LTER scientists will be able to use these data to provide a more quantitative assessment of how aeolian processes may aid in the distribution of nutrients, plants, and animals to terrestrial and aquatic ecosystems in the Dry Valleys. This research will provide quantitative information on the effects of extreme cold and low humidity on transport thresholds and rates, which can be applied to cold desert environments of the Arctic and Antarctic as well as to Mars, and also improve interpretation of Quaternary periglacial aeolian processes.