The seaweed flora of Admiralty Bay, King George Island, Antarctic

Admiralty Bay is located on the western side of King George Island. Although several research teams of different nationalities have carried out surveys in the region for decades, there are only two publications dealing with the seaweed flora of the bay. Here, we report on a taxonomic survey of the seaweeds we collected during the 25th Brazilian Antarctic Expedition (December 2006/November 2007). We discovered 42 species (21 Rhodophyta, 14 Phaeophyceae, and 7 Chlorophyta), corresponding to an increase of about 31% in the seaweed biodiversity hitherto known for the region. Considering that the Antarctic Peninsula, adjacent to King George Island seems to be one of the most rapidly warming spots on the planet, this kind of survey may provide a valuable tool for detecting eventual changes in seaweed biodiversity.

Characterization of organic matter in sediment cores of the Todos os Santos Bay, Bahia, Brazil, by elemental analysis and (13)C NMR

The impact of human activity on the sediments of Todos os Santos Bay in Brazil was evaluated by elemental analysis and (13)C Nuclear Magnetic Resonance ((13)C NMR). This article reports a study of six sediment cores collected at different depths and regions of Todos os Santos Bay. The elemental profiles of cores collected on the eastern side of Frades Island suggest an abrupt change in the sedimentation regime. Auto-regressive Integrated Moving Average (ARIMA) analysis corroborates this result. The range of depths of the cores corresponds to about 50 years ago, coinciding with the implantation of major onshore industrial projects in the region. Principal Component Analysis of the (13)C NMR spectra clearly differentiates sediment samples closer to the Subae estuary, which have high contents of terrestrial organic matter, from those closer to a local oil refinery. The results presented in this article illustrate several important aspects of environmental impact of human activity on this bay. (C) 2011 Elsevier Ltd. All rights reserved.

Salinity influences glutathione S-transferase activity and lipid peroxidation responses in the Crassostrea gigas oyster exposed to diesel oil

Biochemical responses in bivalve mollusks are commonly employed in environmental studies as biomarkers of aquatic contamination. The present study evaluated the possible influence of salinity (35, 25,15 and 9 ppt) in the biomarker responses of Crassostrea gigas oysters exposed to diesel at different nominal concentrations (0.01, 0.1 and 1 mLL(-1)) using a semi-static exposure system. Salinity alone did not resulted in major changes in the gill`s catalase activity (CAT), glutathione S-transferase activity (GST) and lipid peroxidation levels (measured as malondialdehyde. MDA), but influenced diesel related responses. At 25 ppt salinity, but not at the other salinity levels, oysters exposed to diesel showed a strikingly positive concentration-dependent GST response. At 25 ppt and 1 mLL(-1) diesel, the GST activity in the gills remained elevated, even after one week of depuration in clean water. The increased MDA levels in the oysters exposed to diesel comparing to control groups at 9, 15 and 35 ppt salinities suggest the occurrence of lipid peroxidation in those salinities, but not at 25 ppt salinity. The MDA quickly returned to basal levels after 24 h of depuration. CAT activity was unaltered by the treatments employed. High toxicity for 1 mLL(-1) diesel was observed only at 35 ppt salinity, but not in the other salinities. Results from this study strongly suggest that salinity influences the diesel related biomarker responses and toxicity in C. gigas, and that some of those responses remain altered even after depuration. (C) 2011 Elsevier B.V. All rights reserved.