Soap Lake Photosynthetic Biodiversity

Glacial melt lakes may account for the lion's share of our inland fresh water resources. They may also be the prime source of microbial diversity on Earth since their complex, multispecies, interdependent microbial communities have experienced repeated cycles of global warming and freezing across several billion years of geological history. While these lakes may initially form from the fresh water melt of a newly form glacier, later in their life cycle they become hypersaline, alkaline lakes, often known as soap lakes, One such site is Soap Lake near Grand Coulee Dam in central Washington State. As part of a National Science Foundation multidisciplinary project led by Professor Holly Pinkart at Central Washington University to explore the chemistry, biology, and geology of this soda lake, we have collected orbital multispectral and in situ ultraviolet fluorescent imaging data to document seasonal variations in geobiological activity. We have recently begun to assess virus mediation of information transfer between disparate microbial species. Such horizontal gene transfer may be a primary adaptive mechanism for microbial community survival through repeated global warming-freezing cycles and the origin of microbial diversity. Halite crystals deposited during complete evaporation of the warming-freezing cycles trap microbial life can be detected with ultraviolet imaging. The genomes of these entrapped microbes can serve as a window into the evolution of complex adaptive systems. The transfer of information during the current global increase in temperature in Antarctic soda lakes may uncover microbial strategies for adapting catastrophic environmental change in this fragile continent. Soda lakes or their acidic analogues may even have been the last surface refuge of microbial life on ancient Mars as the planet lost most of its atmosphere and water.

References

Storrie-Lombardi, M. C. and Pinkart, H. C. and (2007) Co-evolution of cyanophage and cyanobacteria in Antarctic lakes: Adaptive responses to high UV flux and global warming. Astrobiology and Planetary Missions X. eds/ R. B. Hoover, G. V. Levin and A. Y. Rozanov. 6694 (54), 1-13. Abs_Cyanophage_2007.pdf

Pinkart, H. C. and Storrie-Lombardi, M. C (2007) Diversity, evolution, and horizontal gene transfer (HGT) in soda lakes. Astrobiology and Planetary Missions X. eds. R. B. Hoover, G. V. Levin and A. Y. Rozanov. 6694 (34), 1-11. Abs_Diversity_2007.pdf

Mormile, M. R. and Storrie-Lombardi, M. C (2005) The use of ultraviolet excitation of native fluorescence for identifying biomarkers in halite crystals. Astrobiologoy and Planetary Missions (R. B. Hoover, G. B. Levin, A. Y. Rozanov and G. R. Gladstone, Eds.) Proc. SPIE 5906: 246-253.  Abs_Halides_2004.pdf