Environmental research

Impacts of tourism on wildlife populations at Palmer Station, Antarctica. William Fraser, Montana State University. Tourism in Antarctica has steadily increased since the late 1960s. Despite rising concern that human activity may adversely affect wildlife populations, studies designed to address this issue have been lacking. Our objective is to examine the feasibility of coupling research on the effects of tourism on Adélie penguin populations on Torgersen Island, Antarctic Peninsula, with two long-term ecosystem programs already in existence in the area. The rationale for this approach is that understanding and defining the natural variability inherent in the ecosystem are necessary prerequisites for identifying and interpreting the effects of human activity. By employing identical technologies and methodologies, we will attempt to develop identical, coincident databases at sites visited by tourists to compare with databases developed as part of the two ecosystem studies at sites not visited by tourists. The latter will thus provide the background ecosystem data needed to discern and interpret the former. If we are successful in developing this arrangement, our research will become one of the key studies addressing human impact in Antarctica and will serve as a model for future research of a similar nature. The results of this study will also help fulfill the National Science Foundationís responsibility and obligations for environmental protection under the Antarctic Conservation Act of 1978. (S-013)

Characterization of indigenous and introduced toxic phytoplankton in Antarctica. Donald Anderson, Woods Hole Oceanographic Institution. Of the thousands of species of marine phytoplankton only a few produce potent toxins. These species are found in the massive "red tides" or blooms of cells that discolor the water. More commonly, the organisms are present at low concentrations and are noticed only by the effects their toxins have on aquatic organisms and humans. The nature of the toxic phytoplankton problem has changed considerably in recent years: many areas that were previously unaffected are now subject to recurrent outbreaks. Therefore, it is alarming that marine algal toxins (saxitoxins) have been found in antarctic mollusks.

The implications of this discovery are profound given the low number of trophic levels between primary producers and top predators and the proven ability of the saxitoxins to alter the food web structure and dynamics. Saxitoxins can affect zooplankton, fish larvae, whales, porpoises, seabirds, and humans. A concern is that the saxitoxin-producing alga, presumably the dinoflagellates in the genus Alexandrium, has been introduced to antarctic waters, possibly by vessel traffic between South America and the Antarctic Peninsula. This mechanism of species dispersal has been implicated in the sudden appearance of toxic algae in other areas of the world. Short and frequent transport pathways do exist between Antarctica and the high-toxicity waters of southern Chile and Argentina. It is also possible that the saxitoxins-producing organism is indigenous to Antarctica and was only recently noticed. In either case, the implications to the antarctic food web are significant.

The objectives of this project are to identify and characterize the possible source(s) of saxitoxins in Antarctica to determine whether the causative organisms are indigenous or introduced species, and if introduced, to identify the probable origin and transport pathway. (S-300)

Diagnostic indicators of biological community stress using benthic community analysis to tease apart impacts of organic enrichment and toxicity: An experiment in McMurdo Sound. Charles Peterson, University of North Carolina at Chapel Hill. 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 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 investigators will test the hypothesis that annelid worms and nematodes are enhanced by modest organic loading and arthropods and echinoderms are depressed preferentially by modest exposure to toxic contaminants (trace metals). This hypothesis will be tested near McMurdo Station because

The first objective will be to establish a field experiment near McMurdo Station where the investigators will manipulate organic loading and trace metal concentrations in sediment within colonization trays to test 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 to assess whether biological interactions within the ecosystem with the diagnostic capability of the indices of pollution stress. Second, the investigators 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. (S-302)

The effect of dissolved organic matter on the photolysis and bioaccumulation of synthetic organic compounds in two lakes on Ross Island, Antarctica. Yu-Ping Chin, Ohio State University. The effect of persistent synthetic organic contaminants (SOCs) on the antarctic ecosystems is poorly understood. Dissolved organic matter (DOM) is ubiquitous to all surface waters in Antarctica, and these compounds may play an important role in the fate of SOCs. DOM is capable of acting as a quasisorbent, thereby altering the speciation of SOCs in the water column. DOM is also highly photoreactive and is able to form chemical transients that can transform SOCs. This dual-role nature of DOM could have pronounced effects on the bioavailability of SOCs to aquatic organisms.

This exploratory research will study processes that control the fate of SOCs in the presence of DOM from two small lakes on Ross Island. Bioaccumulation experiments using phytoplankton and cyanobacteria from these sites will be conducted in an effort to understand the effect of DOM on the bioavailability of SOCs. A chlorinated biphenyl congener and pyrene have been selected for study because they represent classes of contaminants found in Antarctica and because they possess a wide range of physiochemical properties. Photolysis experiments using artificial sunlight simulators will be studied to determine the role of DOM as photocatalysts in the transformation of the two target analytes. The results from this exploratory research will provide the groundwork for a much larger field project that will study these processes both in situ and ex situ using other SOCs. (S-305)

Measurement of combustion effluent aerosols from the Amundsen­Scott South Pole Station. Anthony Hansen, Magee Scientific Company. Anthropogenic activities in Antarctica have the potential of producing both contemporaneous and long-term environmental impacts on the nearly pristine surroundings. One of these impacts arises from the emission of "black" or "elemental" carbonaceous aerosols from the exhaust of diesel-powered generators and vehicles used to support antarctic operations. When deposited on the snow and ice cover, this pollutant may be preserved indefinitely. Its high optical absorption will alter the surface albedo and the radiative properties of surface cover. Its ability to promote catalytically certain chemical reactions may lead to modifications of snow and ice chemistry. Its absorbed content of fuel-derived organic species, such as polycyclic aromatic hydrocarbons and other toxics, may have a deleterious effect on marginal biota and near coastal stations.

Previous work showed that extremely small, but detectable, concentrations of black carbon aerosol are brought to the Amundsen­Scott South Pole Station in the background atmosphere in amounts consistent with models of long-range transport; however, the program that made this determination terminated in 1990. A 1986 study of surface snow and ice showed a clear plume of soot downwind of the station. Our objective is to install more modern equipment both upwind and downwind of the South Pole Station to re-establish the background aerosol measurements and to provide a direct assessment of the stationís emissions. The results of our work will contribute to determining the stationís environmental impact resulting from combustion-derived emissions. This information may be used as input to mitigation and abatement strategies. The upwind data will contribute to the global monitoring record and to assessments of the global circulation of anthropogenic emissions capable of influencing atmospheric optics and chemistry. (S-314)