Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Changes in Sea-ice Microbial Community Composition During an Arctic Winter
Eric Collins1, Jody Deming2
1Oceanography, University of Washington, Box 357940, Seattle, WA, 98195, USA, Phone 206-221-5755, rec3141@u.washington.edu
2Oceanography, University of Washington, Box 357940, Seattle, WA, 98195, USA, Phone 206-543-0845, jdeming@u.washington.edu
We hypothesize that microbial communities experiencing similar conditions of environmental extremes will react by altering the species composition of the community in a similar manner. This hypothesis can be tested in sea ice, where microbial communities encased in newly formed sections of the ice at different times during ice growth can be tracked through the winter as they respond to environmental changes. Over the winter, temperatures will decrease dramatically in the ice column (exhibiting a range between –2 and –30°C), causing consequent increases (from seawater salinity to 235 psu) of the brine inclusions -- the inhabitable volume of the ice matrix. During the experiment, we expect to find a decrease in the number of common seawater species and an increase in the representation of psychrophilic (and possibly halophilic) species.
Specifically, we will use molecular techniques, including analysis by fluorescence in situ hybridization and terminal restriction fragment length polymorphism, to provide measures of microbial community composition and diversity in discrete sections of first-year sea ice as functions of time, temperature, and other variables. Measurements will be taken weekly at specific temperature horizons over the course of four months between December 2003 and March 2004. Sample collection and laboratory facilities will be aboard the Amundsen, the Canadian Coast Guard icebreaker newly renovated for science, while frozen into Franklin Bay, Northwest Territories, Canada.
We predict that temperature (as coupled to salinity) is the driving force behind wintertime changes in the microbial community composition of sea ice, not the availability of light, nutrients or organic substrates. If confirmed, we can further predict that microbial diversity in sea ice will be affected greatly over the coming decades, as mean annual global temperatures continue to rise and Arctic winters presumably grow warmer. Extremophiles that today might benefit from the selective forces of an Arctic winter (and benefit society in return, as their genes and enzymes are harnessed for various applications) may be at a distinct disadvantage with only warm thin ice in the future.
Abstract Categories: Changes in the Sea
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