Laura Comoglio

Heavy metal concentrations and biomarkers of oxidative stress in native mussels (Mytilus edulis chilensis) from Beagle Channel coast (Tierra del Fuego, Argentina).

The aim of this study was to evaluate the usefulness of oxidative stress biomarkers of pollution in native mussels Mytilus edulis chilensis from the Beagle Channel. Spatial and seasonal variations of catalase, glutathione-S-transferase and lipid peroxidation in gills and digestive gland were analyzed in relation to environmental parameters, heavy metals in sediment and in tissue. Four sites with anthropogenic impact and a control site were selected and monitored during the four seasons of 2007. We found significant differences among sites in concentrations of dissolved nutrients and heavy metals in sediments, with the highest values recorded at sites with anthropogenic pressure. Different patterns were observed between concentrations of metals in tissues and in sediments suggesting differences in bioavailability. There were also significant differences in biomarker responses among sites, despite the strong seasonal variability. Our results showed relatively moderate levels of pollution in the study area as a result of urban influences.

Starvation effects on physiological parameters and biochemical composition of the hepatopancreas of the southern king crab Lithodes santolla (Molina, 1782)

Este estudio evalua los efectos del ayuno en la centolla Lithodes santolla. Machos adultos de la centolla fueron mantenidos en condiciones de ayuno durante 12 dias. Cada 3 dias (i.e., 0, 3, 6, 9 y 12 dias) se evaluo en subgrupos el consumo de oxigeno, la excrecion de amonio, la relacion atomica O:N y la composicion bioquimica del hepatopancreas. El indice hepatosomatico (calculado individualmente como el porcentaje del peso humedo del hepatopancreas en relacion al peso humedo total del individuo) fue menor a 12 dias de ayuno, coincidiendo con el menor contenido de proteinas en el hepatopancreas. No se detectaron diferencias significativas en la composicion bioquimica porcentual (contenido de agua, materia organica y cenizas). El contenido lipidico no fue significativamente diferente durante el experimento aunque el mayor valor fue registrado a los 3 dias de ayuno. Entre los 3 y 9 dias de ayuno, la excrecion de amonio y el contenido de proteinas en el hepatopancreas fue mayor y la actividad enzimatica de tripsina, menor. Esto podria indicar que el catabolismo de proteinas fue el mas importante durante ese periodo. Este hecho tambien se confirma por los bajos valores de O:N detectados en el periodo mencionado. A los 9 dias de ayuno se incremento el consumo de oxigeno, acompanado con un alto valor de excrecion de amonio, originados probablemente por una demanda extra de energia producida por el ayuno. Se concluye que L. santolla para estos rangos de tiempo experimental utiliza proteinas como fuente primaria de energia.

Use of biomarkers in resident organisms as a tool for environmental monitoring in a cold coastal system, Tierra del Fuego Island.

Antioxidant status of Nacella (P) magellanica and Mytilus edulis related with heavy metal in sediment and tissues were analysed in five stations close to Ushuaia city in winter and spring. The principal component analysis produced a two-dimensional pattern of the degree of similarity between sites. The Industrial-Urban Contamination Index (IUCI) showed that the Industrial Zone (IZ) and Oil Marine Station (OMS) represent areas with anthropic inputs. Heavy metals have differential association with biomarkers depending on the species. In limpets, digestive gland presented major activities of enzyme defence in winter and gonads have shown higher values of Catalase (CAT) during spring while lipid peroxidation (LPO) presented higher values in IZ. For mussels CAT and LPO increased in spring time. For superoxide dismutase (SOD) peaks have been detected in IZ and NW stations for winter. Differences in biomarker responses due to seasons did not influence the grouping of the sites into references and contaminated groups.