INFLUENCE OF SEDIMENT QUALITY ON THE BENTHIC COMMUNITIES OF ADMIRALTY BAY, KING GEORGE ISLAND, ANTARCTICA

Marine benthos is widely used in environmental impact studies, especially in coastal areas. In the summer of 2010, three areas of Martel Inlet and one in Mackellar Inlet were sampled in order to verify the marine environmental status near the Brazilian Station "Comandante Ferraz" (CF). In the shallow sublittoral zone (20 m depth), sediment samples were collected to analyze their physical characteristics, quality and indicators of anthropic activities (grain size, organic matter, phytopigments, linear alkylbenzenes, faecal sterols, microbiological indicators, hydrocarbons, persistent organic pollutants and metals) and to evaluate the meio- and macrofauna communities structure. Meiofauna densities were in the range of those found in previous studies in the bay and did not differ significantly among sampling sites. Nematodes were the dominant group. On the other hand, macrofauna densities were significantly higher in Mackellar Inlet, when comparing with some sites of Martel Inlet. Polychaetes, oligochaetes and bivalves were the dominant macrofauna taxa. Correlation analysis showed that different sediment characteristics could explain the abundance of the meiofauna or the macrofauna groups in a different way. Change in the meio- and macrobenthic community structure was detected at the site under the CF sewage outfall influence (lower density of meiofauna, different taxa composition of macro- and meiofauna), where relatively higher concentrations of linear alkylbenzenes and coprostanol, and densities of Escherichia coli and Clostridium perfringens were found. These results suggest some local impact of human activities on the benthic system in front of the Brazilian Research Station and contribute to the monitoring program under the scope of the INCT-APA (National Institute of Science and Technology - Antarctic Environmental Research).