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The soils of the Dry Valleys are up to five million years
old, and are characterized by poorly developed profiles, low
organic matter and water content and high salinity. Despite
a general appearance of apparent uniformity, Antarctic soils
have a high degree of spatial and temporal heterogeneity in
soil properties, hydrologic regimes, and biological
composition, which we are relating to the general biological
productivity of the dry valleys. The primary research goal
is to understand the carbon cycle in the Dry Valleys with an
emphasis on the sources of carbon (contemporary and legacy),
and their influence upon the distribution and diversity of
soil communities.
We are developing a soil carbon budget for the dry
valleys based upon systematic regional sampling of soil
profiles. The soil organic carbon reservoir far exceeds that
of the more productive, yet spatially-limited, dry valley
lacustrine and stream ecosystems. The natural abundances of
13C and 15N in soil organic matter indicate that the
relative contributions of marine, soil derived, and
lacustrine (recent and paleo) sources to soil carbon pools
are a function of position in the dry valley landscape
(elevation; distance from lakes, streams, or paleolakes;
distance from marine sources). The soil carbon cycle in the
McMurdo region represents an extreme "end-member" of global
soil ecosystems and is a significant component of the
overall carbon cycle of the McMurdo Dry Valleys.
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