Natural and AntHropic Impact Assessment on Biochemical and Histopathological Biomarkers of Fishes and Invertebrates at Coastal Region of Admiralty Bay King George Island

Abstract

Marine environments near the scientific stations and local anchoring of ships are considered potential pollution sites in Antarctica. Human waste, the burning of fuel oil and its possible leakage from ships during transport to the stations are major sources of pollution. The metabolic responses and histopathology of fish and benthic invertebrates of Admiralty Bay, King George Island, are a part of environmental monitoring research proposed in Module 3 INCT-APA for the region. The Antarctic fish Notothenia rossii and Notothenia coriiceps and invertebrates Nacella concinna were selected as target organisms for studies of biomarker responses during the XXVIII Brazilian expedition to Antarctica. The aim of these studies is to establish a baseline for biochemical and histopathological biomarkers and to understand, through bioassays, the effect of pollutants on biological responses of Antarctic organisms. Bioassays with pollutants (fuel oil, sewage and heavy metals) aim to distinguish the biological responses caused by seasonal variations in natural environmental conditions from those imposed by the presence of pollutants in Admiralty Bay ASMA. In aquatic environments, the absorption of toxic substances, mainly by phytoplankton and zooplankton, results in the high concentration of these substances in organisms belonging to higher trophic levels in the food chain. These substances then eventually reach a large number of organisms, including fish and invertebrates. Through the use of different biomarkers it is possible to detect the presence of pollutants in water and sediment, in the organisms that inhabit these environments. Fish and invertebrates are good bioindicators of environmental quality in aquatic ecosystems, since they occupy different positions in the food chain and have varying spatial distribution. These features allow for a direct and indirect evaluation of the health of several components of the aquatic environment. Using histopathological, cellular, biochemical and molecular analysis, the health of fishes and invertebrates, collected directly from nature or through the bioassays, can be evaluated. The histology can be used as a tool for identifying biomarkers of fish fauna and invertebrates. The lesions detected in cells, tissues or organs exposed to pollutants represent an integration of the cumulative effects of these substances at the biochemical and physiological levels (Meyer et al., 2002). Biomarkers are not normally associated with severe adverse effects caused by toxic stress agents. The early biomarker response is much more important as a marker of future adverse biological effects than as an indicator of serious environmental problems. The effects caused by toxic stress agents are often compensated or repaired at the molecular level, without compromising the higher 3