Our lab has been studying soil biodiversity and ecosystem functioning in the McMurdo Dry Valleys since 1989. A major effort has been focussed on the many ecosystem processes that are mediated by soil organisms. For example, they control rates of organic matter decomposition and, consequently, regulate the mass of stored carbon. Despite their importance, the ecological and edaphic factors controlling the distribution and populations of soil fauna are poorly known. Research on soil communities with low diversity, such as in Antarctica, provides an opportunity to elucidate relationships between species diversity, physical and chemical factors, and ecosystem functioning that otherwise are masked by the overwhelming complexity of soil biodiversity found in most terrestrial ecosystems.

Antarctic soils are the oldest, coldest, and driest on Earth and share similarities with the arid soils of the Jornada and Sevilleta LTER sites. The soils found in the McMurdo Dry Valleys are poorly developed, coarse-textured, and often have high salinities. They also have the lowest organic carbon and biological activity of any soils on this planet.

The physical and chemical environment of Antarctic soils varies along gradients of temperature, moisture, organic matter content created in part by legacies of past climates.

No other soil systems are known to exist in which nematodes represent the top of the food chain and where food webs are as simple in structure. The nematode community in MCM soils consists of an endemic species Scottnema lindsayae , a microbial feeder (bacteria and yeast), Plectus antarcticus, a bacterial feeder, and Eudorylaimus antarcticus, an omnivore-predator. Because nematodes are aquatic animals, moisture is a more important factor for survival in Antarctica than low temperature. Moisture from melting snow and streams is available to soils only intermittently, so organisms must be capable of prolonged survival with limited moisture and temperatures below freezing. Nevertheless, nematodes are ideally suited for survival in this extreme environment. They can enter a survival state, anhydrobiosis, for extended periods. This effectively decouples them from the nutrient cycle, which may contribute to the extremely slow rate of nutrient and carbon exchange in the MCM.

Antarctic Research

Publications

Field Research Teams

Outreach

Links

Soil Inventory (.xls)

This material is based on work supported by the National Science Foundation under Grant No. NSF OPP 0229836. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.