Assessing winter bacterioplankton distribution and carbon cycling as part of AMLR field program

Affiliation(s)PIProject periodFunded by
DEES Murray, Alison E 07/12/2012 - 07/12/2013 National Science Foundation

Project Description

The U.S. Antarctic Marine Living Resources (AMLR) field research program will conduct a quantitative survey of the pelagic ecosystem during a short, wintertime field season in the South Shetland Island, Scotia Sea and the NW Weddell Sea regions in August, 2012. This winter expedition follows a 25-year time series program studying austral summer waters, and aims to capture the hydrography and winter distributions of krill for comparisons with summer conditions over this long times series study. The RVIB Nathanial B. Palmer has been chartered as the research platform for this cruise. The proposed effort complements the AMLR program by adding a microbial component to the oceanographic surveys in this important Southern Ocean region. Intellectual Merit: The primary goal of the AMLR winter cruise is to establish the ecological importance of winter processes, particularly as related to sea ice. This effort will help determine how the template for ecological success is set up for summertime production across all trophic levels. The NOAA team does not study the ecosystem at the level of microorganisms beyond determining chlorophyll concentrations. There is significant value-added by inclusion of the proposed research which includes determining the distributions of pico and nanoplankton across the AMLR study region and collecting samples for microbial biomass and organic carbon analysis. This data will improve the understanding of winter bacterioplankton distributions and provide sample collection opportunities for downstream diversity and biogeochemical studies to create an integrated ecosystem picture that will be developed with the NOAA AMLR group. In particular, this effort will extend the geographic coverage of winter bacterioplankton surveys in the South Shetland Islands region, both on and off the continental slope. This is important to test hypotheses concerning wintertime processes that were observed during a recent IPY research program led by Murray where the wintertime community was found to be distinct not only in phylogenetic composition, but in genome-encoded metabolic capacity and proteome expression. Participation in the AMLR cruise will allow for testing of the hypothesis that chemolithoautotrophy is a significant process in winter Antarctic Peninsula surface waters in the AMLR sampling area (both on and off the continental shelf and with respect to different sea ice conditions). Broader Impacts: The impacts of the proposed research extend to the greater oceanographic community that is interested in carbon cycling, and seasonal processes. Data sets such as the one that will be obtained are far and few between in Southern Ocean winter waters, thus the opportunity is highly valuable in this regard. The proposed effort will provide the opportunity for an international (Chilean) first year graduate student to participate in the research cruise, that Murray is a co-advisor of, Carla Gimpel. Ms. Gimpel plans to develop a dissertation program studying Antarctic Peninsula bacterioplankton, and this cruise opportunity comes at an excellent point in her career. Murray will develop a cruise website to post reports from the field, as she has done for other expeditions (e.g. http://iceberg.dri.edu), that targets both a broad lay audience and general science audience.