Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

Metals impact into the Paranaguá Estuarine Complex (Brazil) during the exceptional flood of 2011

Abstract Particulate and dissolved metal concentrations were determined after the largest flood in the last 30 years on the east-west axis of the Paranaguá Estuarine Complex (PEC) and compared to the those of the dry period at two stations. Results confirmed that the flood greatly affected riverine outflows and the behavior of metals in the PEC. In particular, a sharp decrease in salinity was followed by extremely high SPM concentrations leading to a decrease in DO concentrations at both stations. For the dissolved phase, ANOSIM analysis showed a significant dissimilarity at each station between the sampled periods, whereas for the particulate phase this dissimilarity was found only for the samplings taken at the Antonina Station. KD values suggested dissolved Cu behavior was related to the presence of organic complexes and dissolved Mn had sediment resuspension of redox sediments and or/pore water injection as sources. Metal concentrations were lower than in polluted estuaries, though high enrichment factors found after the flood pointed to the influence of anthropogenic sources. In conclusion, the flood's influence was more evident at the Antonina Station, due to its location in the upper estuary, whereas in Paranaguá a high SPM content with low metal concentration was found, following the common pattern generally found in other marine systems subject to heavy rainfall events

Biochemical normalization of trace metals in Arctocephalus Australis

Initially, the heart concentration data does not seem relevant for use as a bioindicator, mainly due to its low concentration level. After applying a normalizing procedure, the heart results were a better Hg bioindicator (preconcentration coefficient 43.1) than those of the kidney (preconcentration coefficient 8.6). Cadmium preconcentration coefficients were 128.1, 195.3 and 5.2 for liver, kidney and heart, respectively, demonstrating the high accumulative capacity especially for the liver and kidneys. Iron is proposed as a normalizing element for the definiton of the regional natural biochemical population of the metals. In general, positive correlation coefficients were found between Fe and other metals.Arctocephalus australis foi usado como organismo indicador para concentrações de metal traço na costa do Rio Grande do Sul. Metais foram analisados em tecidos extraídos do coração, rins e fígado. Os baixos teores encontrados no coração inicialmente poderiam indicar que este órgão não traria resultados relevantes. Porém, mediante a aplicação de um procedimento de normalização, foram encontrados coeficientes de pré-concentração de 43.1 e de 8.6 para o coração e para os rins, respectivamente, indicando o tecido do coração como o melhor bioindicador para Hg. Para Cd, os coeficientes de pré-concentração foram 128.1, 195.3 e 5.2 para fígado, rins e coração, respectivamente, demonstrando alta capacidade acumulativa especialmente para fígado e rins. Foram encontradas altas correlações positivas entre o Fe e os metais Zn, Cu, Cd, Hg, Ag, Mn, Ni, Cr e Pb, indicando ser este elemento normalizante para definição da concentração bioquímica natural de metais na população de Arctocephalus australis no extremo sul do Brasil

Monitoramento da contaminação por elementos traço em ostras comercializadas em Recife, Pernambuco, Brasil Monitoring of trace elements in oysters marketed in Recife, Pernambuco, Brazil

Amostras de ostras comercializadas em Recife, Pernambuco, Brasil, foram monitoradas em relação ao conteúdo de elementos traço (Hg, Zn, Fe, Cu e Mn) durante o período de um ano (março/2001 a fevereiro/2002). Mercúrio foi o principal contaminante encontrado nas ostras e o elemento que apresenta maior risco à saúde pública. Foram encontrados valores de concentração de Hg em ostras de até 551,12µg/kg (peso úmido). Esses valores sugerem que a ingestão de ostras deve ser feita com restrições, principalmente, pela população que vive de sua coleta como forma de subsistência, por crianças, e mulheres grávidas. A avaliação dos níveis de mercúrio em frutos do mar é um importante fator para avaliar o risco de contaminação por mercúrio em pessoas não ocupacionalmente expostas.<br>Samples of oysters marketed in Recife, Pernambuco, Brazil, were monitored for the concentration of trace elements (Hg, Zn, Fe, Cu, and Mn) for one year (from March 2001 to February 2002). Mercury was the principal contaminant found in oysters and the element posing the greatest public health risk. Mercury levels in oysters reached 551.12µg/kg (wet weight). These values suggest that oyster consumption should be restricted, especially among communities that gather them as a subsistence activity, as well as by children and pregnant women. Evaluation of mercury concentration in seafood is an important factor for assessing the risk of contamination among individuals who are not occupationally exposed

The use of oxygen isotopic ratios to identify natural and anthropogenic mercury concentrations in the Lower Brazilian Pantanal

Previous studies in the Amazon Basin and the Upper Pantanal show widespread mercury contamination of fish and water as a result of gold mining, and subsequent volatilization of mercury during the recovery process. A study was initiated to assess whether atmospheric transport of mercury to the south has resulted in elevated levels in water and fish in the Lower Pantanal. Water samples werecollected from streams and rivers from the Pantanal (Mato Grosso do Sul) down into the southernmost state of Brazil (Rio Grande do Sul) for total Hg concentration and oxygen isotopic analyses. Based on oxygen isotopes and conductivity, surface water samples can be considered as mixtures of three endmembers: groundwater, rain and ‘‘aged’’ surface water. Lowest concentrations (\2 ng/L) of total Hg were observed in the northernmost samples, especially those associated with the groundwater sources. Further south, Hg concentrations tended to increase, but higher concentrations ([2 ng/L) likely reflect direct input from more localized watershed sources. Fish collected from streams in the Pantanal had extremely low concentrations of total Hg regardless of their size or feeding habit, although one large carnivorous fish ([2 kg) had concentrations approaching 400 ng/g wet wt. All concentrations, however, were considerably lower than those observed in similar species from the region of the Amazon Basin affected by gold mining