RESUMO
Biochemical biomarkers were evaluated in the barnacle Balanus improvisus (Crustacea: Cirripedia) sampled from both polluted and reference sites in the Patos Lagoon Estuary, Southern Brazil. During winter, higher glutathione S-transferase (GST) activity was recorded in the barnacles from the polluted sites, indicating environmental exposure to contaminants. Relatively low lipid peroxide levels (LPO) were also observed in barnacles from polluted sites, indicating that oxidative stress by lipid peroxidation was not a major threat in barnacles from those sites. Seasonal differences in the GST and total oxyradical scavenging capacity (TOSC) could have contributed to the low LPO levels in the summer relative to the levels in the winter. Catalase activity and metallothionein levels were not affected by contamination or seasonality. The seasonal changes observed in biomarker responses were paralleled by the differences in temperature, which could have affected physiological responses, including the balance between pro-oxidants and antioxidants.
Assuntos
Monitoramento Ambiental/métodos , Estações do Ano , Thoracica/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Brasil , Estuários , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Thoracica/metabolismo , Poluentes Químicos da Água/metabolismoRESUMO
Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses.
Assuntos
Invertebrados/fisiologia , Animais , Biodiversidade , Bivalves/metabolismo , Conservação dos Recursos Naturais , Bases de Dados Factuais , Demografia , Ecologia , Ecossistema , Meio Ambiente , Biologia Marinha/métodos , Oceanos e Mares , Rodófitas/metabolismo , Temperatura , Thoracica/metabolismoRESUMO
On April 26th, 2005, an accident caused a leak of 60,000L of Diesel Oil Type "B", freighted by train wagons upstream on a mangrove area within Guanabara Bay, Southeast Brazil. After the accident, samples from animals with different biological requirements were collected in order to monitor polycyclic aromatic hydrocarbons concentrations for the following 12months. Sessile, mobile, carnivorous, omnivorous, organic detritus feeders, planktivorous and suspension feeders were some of the attributes compared. Concentrations of PAHs did not vary in relation to different dietary habits and the best response was from the sessile suspensivorous barnacles. A background level of <50microgkg(-1) was suggested based on the reference site and on values observed in the following months after the accident. The highest values of PAH concentrations were observed in barnacles in the first month immediately after the spill, decreasing to background levels after few months. Barnacles are suggested as a sentinel species.
Assuntos
Braquiúros/metabolismo , Peixes/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Thoracica/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Vazamento de Resíduos Químicos , Ecossistema , Exposição Ambiental/análise , Monitoramento Ambiental , Petróleo/metabolismo , RhizophoraceaeRESUMO
Seawater is a complex corrosive system, and biofouling is one of the factors that influences corrosion processes. The behaviour of corrosion associated with the development of macrofouling was investigated during the first 6 months of the successional process. Three treatments were compared: the 'Control' treatment (absence of macrofouling); 'Community' treatment, and 'Barnacle' treatment, where other macroorganisms were excluded. In the Community treatment, the dominant organisms were filamentous macroalgae (23.73%), barnacles (17.51%), hydroids (16.96%) and encrusting bryozoans (9.58%). In the Barnacle treatment, the cover varied between 39.38% and 62.50%. The corrosion potential ranged from -665.75 to -517.50 mV(Ag/AgC l((KCl))) and could not be associated with fouling development. The highest corrosion rate in the control suggests that macrofouling provides a protection against mass loss. The highest percentage of localised attacks was found in the Community treatment. This may indicate that not only barnacles, but also other organisms induce localised corrosion.