ABSTRACT

The McMurdo Dry Valleys (MCM) LTER project focuses on aquatic and terrestrial ecosystems in a cold desert region of Antarctica. Located on the western coast of McMurdo Sound it forms the largest relatively ice-free area on the continent yet is still subject to extreme environmental conditions: perennially ice-covered lakes, ephemeral streams, extensive areas of exposed soil, limited precipitation, and salt accumulation. All ecosystems are in some way shaped by climate and material transport yet nowhere is this more apparent than at MCM, where life approaches its environmental limits and subtle changes in climate have a major influence on the generation of liquid water. This in turn produces a cascade of processes influencing biological reproduction, productivity, biodiversity, and biogeochemistry. Research has shown that the Dry Valleys ecosystems are very sensitive to small variations in solar radiation and temperature so, while Antarctic ice sheets respond to climate change on the order of thousands of years, the glaciers, streams, and ice-covered lakes here respond almost immediately.
The overall objectives of MCM are to understand 1) the influence of physical and biological constraints on the structure and function of Dry Valleys ecosystems and 2) the modifying effects of material transport on these ecosystems. The most recent stage of MCM research investigated the legacy of past climate change still strongly overprinting present ecological conditions. This new stage will explore the role of resource legacy and extant processes on determining contemporary biodiversity and ecosystem processes. Hypotheses will be tested through a combination of on-going monitoring and experimental programs plus new research within a vigorous modeling component designed to integrate and synthesize the data on a landscape scale. The new activities will enable biodiversity issues to be addressed in a more definitive manner, especially the interplay between physical dispersion and habitat suitability, and efforts will continue to focus on the integration of the biological processes in both aquatic and terrestrial components of the study site. Stoichiometric and molecular diversity components will be incorporated into the biogeochemistry research to provide a common currency integrating all ecosystem components through the documentation of landscape scale elemental transformations and genetic variation. The broader impacts include the training of graduate and undergraduate students, public education, and international cooperation. Outreach activities include the Schoolyard LTER program, Teachers Experiencing Antarctica, scientific presentations to dignitaries and other visitors to the field site, and the continued dissemination of results in scientific literature and through the lay media.

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