While the study of the phylum Tardigrada has increased greatly in recent years, this research has been hampered by difficulties in obtaining reliable DNA sequence. For example, some researchers still rely solely on morphological identifications to proclaim new species, when DNA sequence would tell a different story. This poster will describe new oligonucleotides, thermal cycler parameters, DNA extraction techniques, and PCR cleanup steps designed to deal with this problem for sequencing single specimens.

Nematodes are the dominant and perhaps best studied soil animals of the Antarctic Dry Valleys, yet the genetic mechanisms by which these nematodes can survive multiple environmental stresses, such as freezing and desiccation, are poorly known. To reveal the molecular genetic mechanisms of anhydrobiotic survival, we investigated gene expression in a desiccation and freeze tolerant Antarctic nematode, Plectus murrayi.

We have developed an autonomous underwater vehicle (AUV) capable of generating for the first time 3-D biogeochemical datasets in the extreme environment of perennially ice-covered Antarctic dry valley lakes. The ENDURANCE (Environmentally Non-Disturbing Under-ice Robotic ANtarctic Explorer) is in the middle of a two year campaign to map the under-ice lake dimensions of West Lake Bonney in the McMurdo Dry Valleys, and is equipped to measure a comprehensive suite of physical and biogeochemical indices in the water column.

The history of perennially ice covered lakes in the McMurdo Dry Valleys (MCM), Antarctica have been extensively studied under the Long Term Ecological Research (LTER) project. The lakes are formed in endorheic basins enclosed by topographic relief or glaciers. Over the past century, the lakes have experienced an overall trend of continuous lake level rise despite decrease in solar radiation (Doran et al, 2002). Variability/increase of lake levels is caused by the sole water source; melt from nearby glaciers during austral summer months.

Stream microbial mats are dynamic communities of phototrophic and heterotrophic organisms that develop over intra-seasonal and inter-seasonal time scales. Diatom community composition is influenced by successional processes and physical and chemical gradients that together act to shape stream benthic habitats. In ephemeral streams of the McMurdo Dry Valleys (Antarctica, MCM LTER), previous work has demonstrated that in streams across the Fryxell Lake Basin, the diatom composition in microbial mat communities is determined largely by the annual and historical flow regime.

In the McMurdo Dry Valleys of Antarctica, glaciers are hydrologically linked to closed-basin lakes at the valley floor by glacial melt water streams. We propose that the dynamics of meltwater generation and sub-stream thaw depth control the potential for the hyporheic zone and benthic communities to influence transport of nutrients and dissolved ions downstream. Little is known about the temporal variability of nutrient fluxes to the Dry Valley lakes.

Rates of biogeochemical cycling in desert ecosystems are inherently constrained by water availability. Water pulses resulting from discrete climate events therefore can significantly alter biogeochemical processes. The McMurdo Dry Valleys of Antarctica, a polar desert region, have experienced discrete warming events that resulted in episodic pulses of water made available through permafrost and snow melt.