Biogeochemistry of the McMurdo Dry Valleys
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The McMurdo Dry Valleys are one of the few ice free regions on the Antarctica continent. Seemingly lifeless, this polar desert is one of the harshest environments on Earth. Yet microbial life has established itself in soils, perennial streams and the permanently ice covered lakes of these Valleys. Nitrogen cycling is intensified in these Valleys, with significant inorganic nitrogen, ammonium and nitrate, found throughout these primitive ecosystems? Our isotopic analysis of soil nitrate established that, like the Atacama, deposition of aerosols dominates the N inputs in the valleys (PDF Link) and is likely the main source of N to the aquatic ecosystems. Questions remain as to how fast the microbial life utilizes atmospheric N, where this utilization is most important, and how other atmospheric anions influence the landscape over time. We hope to return to the Dry Valleys in 2008 as part of the International Polar Year to collect aerosols and soils along a coast-plateau transect and to assess N cycling within Lake Bonney using a suite of isotopic techniques.