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Sources and transport of As, Cu, Cd and Pb in the environmental compartments of Deception Island, Antarctica Texto completo
2013
Mão de Ferro, André | Mota, Ana Maria | Canário, João
Sources and transport processes of As, Cu, Cd and Pb were studied in different environmental compartments of Deception Island, an active volcano in the South Shetland Islands, Antarctica. Element concentrations in fresh water samples are consistent with the lowest values reported elsewhere in Antarctica. Interestingly, higher concentration values of As were found in samples collected in or near spring water courses and its transport may be related with processes of lixiviation in underground waters. While in saline waters Cu and Pb had important punctual sources, concentration values for Cd were consistently high pointing to the existence of a natural and diffuse source possibly related with the hydrothermal activity. The high Si/Al ratio, low carbon content, and a non-significant anthropogenic heavy metal input may explain the surprisingly homogeneous heavy metal content found in sediment samples.
Mostrar más [+] Menos [-]Benthic foraminiferal assemblages and trace metals reveal the environment outside the Pearl River Estuary Texto completo
2013
Li, Tao | Xiang, Rong | Li, Tuanjie
We investigated the distribution patterns of the benthic foraminiferal assemblages outside the Pearl River Estuary in relation to trace metals, organic carbon and sedimentary particle fractions. The study area is unpolluted to moderately polluted by Cr, Cu, Pb and Zn and is completely polluted by Ni. The highest levels are found in the western coastal zone. Spatial distributions of the measured elements are strongly related to the behavior of the sedimentary clay fraction. The analyses of species abundance and community diversity as well as subsequent canonical correspondence analysis were used to reveal the relationship between foraminifera data and environmental parameters. Four sampling site groups established by factor analysis were distributed from the coastal area to the inner shelf. Their distribution patterns have a strong correlation with Cu, Pb and Ba. This research shows that benthic foraminifera can be used as bioindicators of trace metal pollutants outside the Pearl River Estuary.
Mostrar más [+] Menos [-]Characterization of epibenthic and demersal megafauna at Mississippi Canyon 252 shortly after the Deepwater Horizon Oil Spill Texto completo
2013
Valentine, Marla M. | Benfield, Mark C.
The Deepwater Horizon Oil Spill resulted in the release of a large quantity of oil and gas into the northern Gulf of Mexico from a bathypelagic source. Due to a lack of pre-spill quantitative data the baseline condition of the communities near the spill site is unknown. This makes it difficult to determine the impact of the spill on deepwater megafauna. Remotely operated vehicles were used to quantify megafauna at five study sites during August and September 2010:2000m north, west, south, and east, and 500m north of the Macondo well. Comparisons of animal abundances indicated that 2000m-N and 2000m-W had the greatest taxonomic richness and highest abundances while 2000m-E had slightly lower values. In contrast 500m-N and 2000m-S had the lowest taxonomic richness and abundances. Our study also suggests that certain taxa were potentially more resistant or sensitive to the spill.
Mostrar más [+] Menos [-]Heavy metals distribution and contamination in surface sediments of the coastal Shandong Peninsula (Yellow Sea) Texto completo
2013
Li, Guogang | Hu, Bangqi | Bi, Jianqiang | Leng, Qinuan | Xiao, Chunqiao | Yang, Zhongcheng
Selected heavy metals (Cr, Cu, Ni, Pb and Zn) in surface sediments from the coastal Shandong Peninsula (Yellow Sea) have been determined to evaluate the spatial distribution and potential ecological risk. Results showed that heavy metal concentrations in the sediments generally met the criteria of China Marine Sediment Quality. However, both the enrichment factor (EF) and geoaccumulation index (Igeo) values suggested the elevation of Pb concentration in the region. Based on the effect-range classification (TEL-PEL SQGs), Cr, Cu and Ni were likely to pose environment risks. Spatial distribution of ecotoxicological index (mean-PEL-quotient) suggested that most of the surface sediments have a 21% probability of being toxic. Similar results were also obtained by pollution load index (PLI). The spatial distribution pattern of heavy metal in surface sediments is a basis for undertaking appropriate action to protect marine sediment quality.
Mostrar más [+] Menos [-]Biological impacts of enhanced alkalinity in Carcinus maenas Texto completo
2013
Cripps, Gemma | Widdicombe, Stephen | Spicer, John I. | Findlay, Helen S
Biological impacts of enhanced alkalinity in Carcinus maenas Texto completo
2013
Cripps, Gemma | Widdicombe, Stephen | Spicer, John I. | Findlay, Helen S
Further steps are needed to establish feasible alleviation strategies that are able to reduce the impacts of ocean acidification, whilst ensuring minimal biological side-effects in the process. Whilst there is a growing body of literature on the biological impacts of many other carbon dioxide reduction techniques, seemingly little is known about enhanced alkalinity. For this reason, we investigated the potential physiological impacts of using chemical sequestration as an alleviation strategy. In a controlled experiment, Carcinus maenas were acutely exposed to concentrations of Ca(OH)2 that would be required to reverse the decline in ocean surface pH and return it to pre-industrial levels. Acute exposure significantly affected all individuals’ acid–base balance resulting in slight respiratory alkalosis and hyperkalemia, which was strongest in mature females. Although the trigger for both of these responses is currently unclear, this study has shown that alkalinity addition does alter acid–base balance in this comparatively robust crustacean species.
Mostrar más [+] Menos [-]Biological impacts of enhanced alkalinity in Carcinus maenas Texto completo
2013
Cripps, Gemma | Widdicombe, Stephen | Spicer, John I | Findlay, Helen S
Further steps are needed to establish feasible alleviation strategies that are able to reduce the impacts of ocean acidification, whilst ensuring minimal biological side-effects in the process. Whilst there is a growing body of literature on the biological impacts of many other carbon dioxide reduction techniques, seemingly little is known about enhanced alkalinity. For this reason, we investigated the potential physiological impacts of using chemical sequestration as an alleviation strategy. In a controlled experiment, Carcinus maenas were acutely exposed to concentrations of Ca(OH)2 that would be required to reverse the decline in ocean surface pH and return it to pre-industrial levels. Acute exposure significantly affected all individuals' acid-base balance resulting in slight respiratory alkalosis and hyperkalemia, which was strongest in mature females. Although the trigger for both of these responses is currently unclear, this study has shown that alkalinity addition does alter acid-base balance in this comparatively robust crustacean species.
Mostrar más [+] Menos [-]Quantitative analysis of plastic debris on recreational beaches in Mumbai, India Texto completo
2013
Jayasiri, H.B. | Purushothaman, C.S. | Veṇṇilā,
Plastic litter was quantified on four sandy beaches in Mumbai. The mean abundance of 7.49g and 68.83 items per square metre was recorded. The abundance of plastics significantly varied among the beaches showing an increasing trend in the southern part. The abundance of plastics by weight in Dadar was significantly higher than that in Aksa. The size fractionation of plastics proved that small particles (1–20mm) are predominant with 41.85% microplastics (1–5mm) which emphasizes the high risk to marine organisms due to possible ingestion. The highest quantity of microplastics was seen in Juhu beach (55.33%) followed by Versova, Aksa and Dadar. The major contributing factors for the abundance are beach usage for different activities such as recreational, religious and fishing which suggest that the land-based sources provide major inputs to plastic pollution in these beaches.
Mostrar más [+] Menos [-]Spatial and long-term analyses of reference and sewage-impacted sites in the SW Atlantic (38°S, 57°W) for the assessment of sensitive and tolerant polychaetes Texto completo
2013
Sánchez, María A. | Jaubet, María L. | Garaffo, Griselda V. | Elías, Rodolfo
Discharges of effluent in urbanized littoral areas produce nonlinear changes in benthic organisms. Data on the composition of the benthic community are often used to obtain environmental quality classifications that serve to indicate the health of the environment. This study conducted a comparative analysis of the polychaetes associated with mussel beds and related these results to the values of environmental variables at both reference and sewage-impacted sites over a 10year period in a rocky intertidal habitat on the coast of the SW Atlantic. The results of the study showed spatial and temporal differences in the abundance and dominance of the polychaetes. The study also furnished evidence of a decrease in the environmental quality of the area. This study allowed the classification of the polychaetes into ecological groups, facilitating the calculation of environmental quality indexes.
Mostrar más [+] Menos [-]Broad-scale patterns of tissue-δ15N and tissue-N indices in frondose Ulva spp.; Developing a national baseline indicator of nitrogen-loading for coastal New Zealand Texto completo
2013
Barr, Neill G. | Dudley, Bruce D. | Rogers, Karyne M. | Cornelisen, Christopher D.
A survey of tissue-δ15N and tissue-N values in the green macroalga, Ulva, was conducted around the coast of New Zealand to determine if these indices could be used as indicators of anthropogenic nutrient loading in coastal waters. In addition, data from four case studies showed temporal and spatial responses of tissue-δ15N and tissue-N in Ulva to significant terrestrial nutrient inputs. Tissue-δ15N in Ulva from ‘natural’ exposed coastal sites showed a relatively narrow baseline range of values (6.6±0.1–8.8±0.1‰) in both summer and winter that was consistent throughout New Zealand. Departures in Ulva tissue-δ15N ratios outside this range, particularly when coupled with high (>3.1%) tissue-N values, indicate significant contributions of terrestrially-derived nitrogen to coastal seawater. We note that tissue-N content is also affected by exposure, light and season; however provided such factors are taken into account Ulva can be a cost-effective indicator of relative changes in both source and amount of nitrogen-loading.
Mostrar más [+] Menos [-]Chemometric evaluation of the heavy metals distribution in waters from the Dilovası region in Kocaeli, Turkey Texto completo
2013
Bingöl, Deniz | Ay, Ümit | Karayünlü Bozbaş, Seda | Uzgören, Nevin
The main objective of this study was to test water samples collected from 10 locations in the Dilovası area (a town in the Kocaeli region of Turkey) for heavy metal contamination and to classify the heavy metal (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb and Hg) contents in water samples using chemometric methods. The heavy metals in the water samples were identified using inductively coupled plasma-mass spectrometry (ICP-MS). To ascertain the relationship among the water samples and their possible sources, the correlation analysis, principal component analysis (PCA), and cluster analysis (CA) were used as classification techniques. About 10 water samples were classified into five groups using PCA. A very similar grouping was obtained using CA.
Mostrar más [+] Menos [-]Microbiological composition of native and exotic clams from Tagus estuary: Effect of season and environmental parameters Texto completo
2013
Anacleto, Patrícia | Pedro, Sónia | Nunes, Maria Leonor | Rosa, Rui | Marques, António
The influence of seasonal and environmental parameters on the occurrence of bacteria was investigated in two clam species (Venerupis pullastra and Ruditapes philippinarum), water and sediment from the Tagus estuary. Total viable counts (TVC), Escherichia coli, Salmonella spp. and Vibrio spp. were evaluated during one-year. Overall, significant seasonal variations were found in both sampling sites, especially for E. coli and Vibrio spp. levels. In summer, significantly higher Vibrio spp. levels were found in R. philippinarum and sediment samples, but not in V. pullastra clams and water samples. In contrast, significantly higher TVC and E. coli levels were observed in winter months in water and sediment samples. Salmonella spp. was generally isolated when higher levels of E. coli were detected, particularly in R. philippinarum. This study is useful for authorities to develop monitoring strategies for coastal contamination and to estimate human health risks associated with the consumption of bivalves.
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