Wednesday, August 6, 2008

PS 34-5: Biodiversity of marine invertebrates of the Antarctic Peninsula

Katrina M. Weber, Ruth Rodriguez, and Vanessa L. Lougheed. University of Texas at El Paso

Background/Question/Methods

The waters of the Antarctic littoral zone are characterized by low salinity, high nutrient levels, and heavy mixing. This area of the Southern Ocean supports a surprisingly diverse community of zooplankton, including amphipods, copepods, ostracods, euphasiids, mysids, rotifers, and protozoans. To investigate the biodiversity of this region and the environmental parameters that control this diversity, ten sites were sampled in the nearshore waters of the Southern Ocean. Six of the sites were in the South Shetland Islands, while the remaining four were sampled near or on the Antarctic Peninsula. Water samples were collected with a plankton net and zooplankton species identified to determine species composition and richness. In related studies, water nutrient and chlorophyll data was also collected at each site.

Results/Conclusions

Similarity in zooplankton species composition between sites was compared using a Jaccard index, which showed a geographical difference in species composition. Initial counts indicate that nearshore zooplankton communities in the South Shetlands were more similar to each other, than they were to continental sites. It is likely that more mixing is occurring among waters in similar regions, resulting in this distribution of species. Species richness and abundance of zooplankton was not shown to be correlated with water nutrient levels; however, more detailed counts will be performed to elucidate any further relationships.