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结果 1561-1570 的 4,042
Dissimilatory nitrate reduction to ammonium conserves nitrogen in anthropogenically affected subtropical mangrove sediments in Southeast China 全文
2016
Cao, Wenzhi | Yang, Jingxin | Li, Ying | Liu, Baoli | Wang, Feifei | Chang, Changtang
In this study, basic sediment properties, nutrient flux, and nitrogen cycle (including denitrification, anaerobic ammonium oxidation [anammox], nitrification, and dissimilatory nitrate reduction to ammonium [DNRA]) were investigated at two sampling sites with different tree ages in the mangrove region of the Jiulong River Estuary, China. The results show that sediments at mangrove flat area have relatively strong capability to reduce NO3−, in which the DNRA rate is relatively high (204.53±48.32μmolNm−2h−1), which is approximately 75.7–85.9% of the total NO3− reduction, while the denitrification and anammox rates are relatively low – only approximately 5.6–9.5% and 8.5–14.8% of the total NO3− reduction, respectively. Thus, in the nitrogen-enriched subtropical mangrove system, DNRA is the main pathway to reduce NO3−, and most of the input nitrogen is conserved as NH4+ in the system, which assures high productivity of the mangrove system.
显示更多 [+] 显示较少 [-]Integrated assessment of biomarker responses and microbiological analysis of oysters from São Luís Island, Brazil 全文
2016
Ribeiro, E.B. | Bastos, L.S. | Galeno, L.S. | Mendes, R.S. | Garino, F. | Carvalho-Neta, R.N.F. | Costa, F.N.
This study was conducted to evaluate the use of biochemical biomarkers and microbiological analysis to identify levels of oyster contamination at different ports in São Luís Island (Maranhão), Brazil. Oysters were analyzed for total coliforms, thermotolerant coliforms, Escherichia coli and Aeromonas spp. In addition, tissue was removed from the digestive gland to determine the glutathione-S-transferase (GST) and catalase (CAT) activity. The highest percentage of microbiological contamination of oyster samples occurred during the rainy season. The activity of GST and catalase in oysters was also higher in the rainy season, coinciding with the greatest abundance of total and thermotolerant coliforms. Among the prospective biomarkers, GST showed the best results for identification of areas with higher levels of contamination.
显示更多 [+] 显示较少 [-]Regional assessment of persistent organic pollutants in resident mussels from New Jersey and New York estuaries following Hurricane Sandy 全文
2016
Smalling, Kelly L. | Deshpande, Ashok D. | Galbraith, Heather S. | Sharack, Beth L. | Timmons, DeMond | Baker, Ronald J.
Resident mussels are effective indicators of ecosystem health and have been utilized in national assessment and monitoring studies for over two decades. Mussels were chosen because contaminant concentrations in their tissues respond to changes in ambient environmental levels, accumulation occurs with little metabolic transformation and a substantial amount of historic data were available. Mussels were collected from 10 previously studied locations approximately a year after Hurricane Sandy. Regionally, concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) decreased significantly, while concentrations of organochlorine pesticides (OCPs) remained unchanged, and polybrominated diphenyl ethers (PBDEs) increased compared to historic concentrations. Although concentrations of PCBs, OCPs and PAHs were at or near record low concentrations, long-term trends did not change after Hurricane Sandy. To effectively measure storm-induced impacts it is necessary to understand the factors influencing changes in mussel body burdens and have a long-term monitoring network and an ability to mobilize post event.
显示更多 [+] 显示较少 [-]Local bleaching thresholds established by remote sensing techniques vary among reefs with deviating bleaching patterns during the 2012 event in the Arabian/Persian Gulf 全文
2016
Shuail, Dawood | Wiedenmann, Jörg | D'Angelo, Cecilia | Baird, Andrew H. | Pratchett, Morgan S. | Riegl, Bernhard | Burt, John A. | Petrov, Peter | Amos, Carl
A severe bleaching event affected coral communities off the coast of Abu Dhabi, UAE in August/September, 2012. In Saadiyat and Ras Ghanada reefs ~40% of the corals showed signs of bleaching. In contrast, only 15% of the corals were affected on Delma reef. Bleaching threshold temperatures for these sites were established using remotely sensed sea surface temperature (SST) data recorded by MODIS-Aqua. The calculated threshold temperatures varied between locations (34.48°C, 34.55°C, 35.05°C), resulting in site-specific deviations in the numbers of days during which these thresholds were exceeded. Hence, the less severe bleaching of Delma reef might be explained by the lower relative heat stress experienced by this coral community. However, the dominance of Porites spp. that is associated with the long-term exposure of Delma reef to elevated temperatures, as well as the more pristine setting may have additionally contributed to the higher coral bleaching threshold for this site.
显示更多 [+] 显示较少 [-]Digestive enzymatic patterns as possible biomarkers of endocrine disruption in the red mullet (Mullus barbatus): A preliminary investigation 全文
2016
Caruso, Gabriella | De Pasquale, Francesca | Mita, Damiano Gustavo | Micale, Valeria
During two seasonal trawl surveys (April and October, 2012), red mullet specimens were caught from two sites of the northern Sicilian coast (Western Mediterranean), characterized by different degrees of pollution, to assess whether their digestive enzymes could be cost-effective diagnostic tools for endocrine disruption. Pepsin, chymotrypsin, carboxypeptidases A and B, amylase and lipase were measured in the digestive tract of each fish. During both samplings, significant differences in the digestive enzymatic patterns of fish collected from the two sites were found. In April, pepsin and lipase contents were significantly lower in fish from the most impacted site than in those from the reference site. In October, the enzymatic patterns showed trends different from spring, with controversial results for carboxypeptidases A and B and amylase. Pepsin and lipase patterns suggest a detrimental effect played by organic pollutants and the use of these enzymes as possible biomarkers of exposure to endocrine disruptors.
显示更多 [+] 显示较少 [-]Response of free-living marine nematodes to the southern Yellow Sea Cold Water Mass 全文
2016
Xu Man, | Liu, Qinghe | Zhang, Zhinan | Liu, Xiaoshou
The Yellow Sea Cold Water Mass is a remarkable seasonal hydrographic event in the bottom water of the Yellow Sea. In order to reveal the response of free-living marine nematodes to this event, community structure and biodiversity indices of nematodes were studied in June and November 2013. The dominant species were Dorylaimopsis rabalaisi, Spilophorella sp., Daptonema sp., Sabatieria sp. and Parasphaerolaimus sp. In terms of trophic structure, epigrowth feeders were the most dominant group. Correlation analysis showed that Shannon–Wiener diversity index had significantly negative correlation with sediment silt–clay percentage, organic matter content and water content. Results of BIOENV indicated that sediment phaeophorbide content, water content, bottom water salinity and temperature were the most important factors related to nematode community. In conclusion, community structure and biodiversity indices of nematodes were consistent in the two sampling seasons.
显示更多 [+] 显示较少 [-]Ingestion of marine litter by loggerhead sea turtles, Caretta caretta, in Portuguese continental waters 全文
2016
Nicolau, Lídia | Marçalo, Ana | Ferreira, Marisa | Sá, Sara | Vingada, José | Eira, Catarina
The accumulation of litter in marine and coastal environments is a major threat to marine life. Data on marine litter in the gastrointestinal tract of stranded loggerhead turtles, Caretta caretta, found along the Portuguese continental coast was presented. Out of the 95 analysed loggerheads, litter was present in 56 individuals (59.0%) and most had less than 10 litter items (76.8%) and less than 5g (dm) (96.8%). Plastic was the main litter category (frequency of occurrence=56.8%), while sheet (45.3%) was the most relevant plastic sub-category. There was no influence of loggerhead stranding season, cause of stranding or size on the amount of litter ingested (mean number and dry mass of litter items per turtle). The high ingested litter occurrence frequency in this study supports the use of the loggerhead turtle as a suitable tool to monitor marine litter trends, as required by the European Marine Strategy Framework Directive.
显示更多 [+] 显示较少 [-]Bioindicators as metrics for environmental monitoring of desalination plant discharges 全文
2016
de-la-Ossa-Carretero, J.A. | Del-Pilar-Ruso, Y. | Loya-Fernández, A. | Ferrero-Vicente, L.M. | Marco-Méndez, C. | Martinez-Garcia, E. | Giménez-Casalduero, F. | Sánchez-Lizaso, J.L.
Bioindicators as metrics for environmental monitoring of desalination plant discharges 全文
2016
de-la-Ossa-Carretero, J.A. | Del-Pilar-Ruso, Y. | Loya-Fernández, A. | Ferrero-Vicente, L.M. | Marco-Méndez, C. | Martinez-Garcia, E. | Giménez-Casalduero, F. | Sánchez-Lizaso, J.L.
Development of desalination projects requires simple methodologies and tools for cost-effective and environmentally-sensitive management. Sentinel taxa and biotic indices are easily interpreted in the perspective of environment management. Echinoderms are potential sentinel taxon to gauge the impact produced by brine discharge and the BOPA index is considered an effective tool for monitoring different types of impact. Salinity increase due to desalination brine discharge was evaluated in terms of these two indicators. They reflected the environmental impact and recovery after implementation of a mitigation measure. Echinoderms disappeared at the station closest to the discharge during the years with highest salinity and then recovered their abundance after installation of a diffuser reduced the salinity increase. In the same period, BOPA responded due to the decrease in sensitive amphipods and the increase in tolerant polychaete families when salinities rose. Although salinity changes explained most of the observed variability in both indicators, other abiotic parameters were also significant in explaining this variability.
显示更多 [+] 显示较少 [-]Bioindicators as metrics for environmental monitoring of desalination plant discharges 全文
2016
de-la-Ossa-Carretero, Jose Antonio | Del-Pilar-Ruso, Yoana | Loya-Fernández, Angel | Ferrero-Vicente, Luis Miguel | Marco-Méndez, Candela | Martinez-Garcia, Elena | Gimenez-Casalduero, Francisca | Sánchez-Lizaso, José Luis | Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada | Biología Marina | Recursos Hídricos y Desarrollo Sostenible
Development of desalination projects requires simple methodologies and tools for cost-effective and environmentally-sensitive management. Sentinel taxa and biotic indices are easily interpreted in the perspective of environment management. Echinoderms are potential sentinel taxon to gauge the impact produced by brine discharge and the BOPA index is considered an effective tool for monitoring different types of impact. Salinity increase due to desalination brine discharge was evaluated in terms of these two indicators. They reflected the environmental impact and recovery after implementation of a mitigation measure. Echinoderms disappeared at the station closest to the discharge during the years with highest salinity and then recovered their abundance after installation of a diffuser reduced the salinity increase. In the same period, BOPA responded due to the decrease in sensitive amphipods and the increase in tolerant polychaete families when salinities rose. Although salinity changes explained most of the observed variability in both indicators, other abiotic parameters were also significant in explaining this variability. | These surveys were funded by the Mancomunidad de Canales del Taibilla.
显示更多 [+] 显示较少 [-]Atmospheric consequences of trade and human development: A case of BRIC countries 全文
2016
Sinha, Avik | Sen, Sudipta
This paper looks into the causal association between economic growth, CO2 emission, trade volume, and human development indicator for Brazil, Russia, India, and China (BRIC countries) during 1980–2013. Following a generalized method of moments (GMM) technique, we have found out that bidirectional causality exists between CO2 emissions and economic growth. Feedback hypothesis is supported between CO2 emissions and human development, trade volume and human development, economic growth, and human development, and CO2 emissions and trade volume. Apart from finding out the unidirectional association from trade volume to economic growth, this study also validated the existence of Environmental Kuznets curve. Empirical findings of the study substantiate that the policymakers of the BRIC nations must focus on the green energy initiatives, either by in-house development or by technology transfer. This movement will allow them to control the ambient air pollution prevalent in these nations.
显示更多 [+] 显示较少 [-]Islands in the oil: Quantifying salt marsh shoreline erosion after the Deepwater Horizon oiling 全文
2016
Turner, R Eugene | McClenachan, Giovanna | Tweel, Andrew W.
Qualitative inferences and sparse bay-wide measurements suggest that shoreline erosion increased after the 2010 BP Deepwater Horizon (DWH) disaster, but quantifying the impacts has been elusive at the landscape scale. We quantified the shoreline erosion of 46 islands for before and after the DWH oil spill to determine how much shoreline was lost, if the losses were temporary, and if recovery/restoration occurred. The erosion rates at the oiled islands increased to 275% in the first six months after the oiling, were 200% of that of the unoiled islands for the first 2.5years after the oiling, and twelve times the average land loss in the deltaic plain of 0.4%y−1 from 1988 to 2011. These results support the hypothesis that oiling compromised the belowground biomass of the emergent vegetation. The islands are, in effect, sentinels of marsh stability already in decline before the oil spill.
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