Diagnostic Indicators of Biological Community: An Experimental Test in McMurdo Sound, Antarctica

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ABSTRACT OPP-96-15849 Communities of benthic invertebrates are widely used to monitor and evaluate biological impacts of pollution in the marine environment because their sessile life styles, longevity, functional diversity, well-known taxonomy and ecological significance render this system an ideal ecological template on which biological consequences are imprinted. Benthic communities have been used successfully in environmental assessments for convincing demonstrations that impacts of pollution are readily detectable at the level of family and phylum for macrofaunal invertebrates. This ability to detect pollution impacts at high taxonomic levels appears to be a consequence of different taxa responding to two classes of benthic communities, organic loading and toxicity, in opposite ways. This project is designed to test the hypothesis that indices of abundance and production for individual phyla of macrofauna and/or meiofauna can be used as independent diagnostics to tease apart the typically confounded impacts of these two separate classes of marine pollution. The PIs will test the hypothesis that annelid worms and nematodes are enhanced by modest organic loading and that arthropods and echinoderms are depressed preferentially by modest exposure to toxic contaminants (trace metals). The first hypothesis will be tested near McMurdo Station because of 1) its relatively constant environment allows experimental work to proceed on the seafloor without compromise by confounding disturbances; 2) previous benthic studies at this site have revealed significant confounded patterns of sediment contamination and benthic community degradation; and 3) low rates of natural bioremediation in cold polar oceans make study of pollution impacts especially critical at high latitudes. The first objective will be to establish a field experiment near McMurdo Station where they will manipulate organic loading and trace meta l concentration in sediments within colonization trays so as to test by factorial design (permitting tests of interactions between factors) whether the separate taxa respond independently to the classes of pollution. Treatments will also include access of larger mobile predators and time for community development so as to assess whether biological interactions within the ecosystem with the diagnostic capability of the indices of pollution stress. Second, the PIs will complete a rigorous review and meta-analysis of all available data sets on effects of pollution on marine invertebrate communities to test the hypothesis using the wealth of pre-existing information from monitoring discharges, oil spills, and previous experimentation. Results have great potential to allow the establishment of diagnostic indicators of community stress that can be used to separate confounded causes of causes of marine pollution and direct appropriate management responses at McMurdo Station