خيارات البحث
النتائج 1 - 10 من 54
Seabirds, gyres and global trends in plastic pollution النص الكامل
2015
van Franeker, Jan A. | Law, Kara Lavender
Fulmars are effective biological indicators of the abundance of floating plastic marine debris. Long-term data reveal high plastic abundance in the southern North Sea, gradually decreasing to the north at increasing distance from population centres, with lowest levels in high-arctic waters. Since the 1980s, pre-production plastic pellets in North Sea fulmars have decreased by ∼75%, while user plastics varied without a strong overall change. Similar trends were found in net-collected floating plastic debris in the North Atlantic subtropical gyre, with a ∼75% decrease in plastic pellets and no obvious trend in user plastic. The decreases in pellets suggest that changes in litter input are rapidly visible in the environment not only close to presumed sources, but also far from land. Floating plastic debris is rapidly “lost” from the ocean surface to other as-yet undetermined sinks in the marine environment.
اظهر المزيد [+] اقل [-]Uptake, release, and absorption of nutrients into the marine environment by the green mussel (Perna viridis) النص الكامل
2015
Srisunont, Chayarat | Babel, Sandhya
The nutrient uptake and release by the mussels in relation with amount of food consumption are emphasised in this research. Results of the study demonstrate that about 16% of the total mass dry weight food consumed by the mussels was released as faeces. The depositions of particulate carbon, nitrogen, and phosphorus in mussel faeces were found to be 26.3, 5.7, and 0.6mg/day/indv respectively. Soluble inorganic nutrients such as NH4+-N (2.5mg/day/indv), and PO43−-P (0.6mg/day/indv) were also released as mussel excretion. The nutrient absorption efficiency for the green mussel body was found to be 65.1% for carbon, 62.1% for nitrogen, and 79.2% for phosphorus. Subsequently, green mussels can remove particulate carbon, nitrogen and phosphorus at 108.1, 13.5, and 4.6mg/day/indv from aquatic systems. Finally, the results can help in estimating the carrying capacity of mussel cultivation without deteriorating the water quality in marine ecosystems.
اظهر المزيد [+] اقل [-]A preliminary assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in deep-sea sediments from the Indian Ocean النص الكامل
2015
Cheng, Zhineng | Lin, Tian | Xu, Weihai | Xu, Yue | Li, Jun | Luo, Chunling | Zhang, Gan
Ten surface sediments were collected from the open Indian Ocean at depths below 4000m in 2011, for the analysis of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). The concentrations of Σ32 PCBs, Σ7 PBDEs, and BDE-209 were 120–514, 49–152, and 7–133pg/g, respectively. These concentrations are close to the lowest values recorded in the global marine environment. The PCBs had a relatively uniform composition, and were dominated by low chlorinated congeners. The concentrations of di-, tri-, and tetra-PCBs were strongly correlated with the total organic carbon (TOC), suggesting the dissolved PCBs were derived from the atmosphere via diffusive air–water exchange, and absorbed by phytoplankton. A high proportion of BDE209 was only detected in the sediment of the low fan of the Ganga River. There were weak correlations between low brominated BDEs and TOC, implying the degradation of BDE209 is a possible source of lower-brominated BDEs in deep-sea sediments.
اظهر المزيد [+] اقل [-]Probabilistic ecological risk assessment of copper in Chinese offshore marine environments from 2005 to 2012 النص الكامل
2015
Jin, Xiaowei | Liu, Fang | Wang, Yeyao | Zhang, Lingsong | Li, Zhao | Wang, Zijian | Giesy, John P. | Wang, Zhen
The objective of the present study was to conduct a probabilistic assessment of risk posed by copper found in the coastal marine environment of China from 2005 to 2012. This was achieved by applying a tiered ecological risk assessment (ERA) approach for characterization of risks of concentrations of copper from nationwide marine water monitoring program. The results show that from 2005 to 2012 the overall trend of hazard quotients (HQs) in the coastal marine environment of China the proportion of locations that exceed a HQ of 1.0 decreased from 64% in 2005 to 31% in 2012. While this indicates an overall improvement of the environment, there still have potential ecological risks in the most of the area, especially for the major gulfs of Liaodong and Bohai Bays and Yellow River Estuary. In addition, probabilities of exceeding the toxicity threshold for 5% of species were 27.6%, 5.4%, 4.9%, 0.8%, 0.4%, 1.0%, 1.8% and 0.12% annually between 2005 and 2012, respectively.
اظهر المزيد [+] اقل [-]Plastic in surface waters of the Inside Passage and beaches of the Salish Sea in Washington State النص الكامل
2015
Davis, Wallace | Murphy, Anne G.
We summarize results of two independent studies on plastic pollution in the marine environment that overlap in time and space. One study evaluated the abundance of anthropogenic debris on 37 sandy beaches bordering the Salish Sea in Washington State while the other characterized plastic debris in surface waters of the Salish Sea and the Inside Passage to Skagway, Alaska. Both studies concluded that foam, primarily expanded polystyrene was the dominant pollutant. Plastic was found in surface waters the full length of the Inside Passage but was concentrated near harbors. At the wrack line, an average square meter of Washington’s 1180km of sandy beaches in the Salish Sea had 61 pieces of anthropogenic debris weighing approximately 5g. The total loading for the entire 1m wide band is estimated to be 72,000,000 pieces and 5.8metric tons. Most anthropogenic debris on beaches is generated within the region.
اظهر المزيد [+] اقل [-]Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia النص الكامل
2015
Maes, Christophe | Blanke, Bruno
Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia النص الكامل
2015
Maes, Christophe | Blanke, Bruno
Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2–3months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation.
اظهر المزيد [+] اقل [-]Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia النص الكامل
2015
Maes, Christophe | Blanke, Bruno
Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2–3 months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation.
اظهر المزيد [+] اقل [-]Occurrence of microplastics in the coastal marine environment: First observation on sediment of China النص الكامل
2015
Qiu, Qiongxuan | Peng, Jinping | Yu, Xubiao | Chen, Fangchaizi | Wang, Jundong | Dong, Fenqiang
Microplastics in sediments from the Beibu Gulf and the coastline of China Sea were investigated to evaluate the occurrence and abundance of microplastics in China for the first time. Microplastics (<5mm) were taken from sediments by a flotation method. The number of microplastics was counted by a fluorescence microscope, an instrument that is rarely used in the detection of microplastics in sediments. This instrument led to results that were satisfactory. Compared with other sampled areas, microplastics were found in massive concentrations in China. Four types of microplastics, HDPE, PET, PE and PS, were identified. The results will provide useful background information for further investigations.
اظهر المزيد [+] اقل [-]Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study النص الكامل
2015
Skeff, Wael | Neumann, Christine | Schulz-Bull, Detlef E.
Water samples from ten German Baltic estuaries were collected in 2012 in order to study the presence of the herbicide glyphosate, its primary metabolite AMPA and their potential transport to the marine environment. For the analyses an LC–MS/MS based analytical method after derivatization with FMOC-Cl was optimized and validated for marine water samples. All investigated estuarine stations were contaminated with AMPA and nine of them also with glyphosate. Concentration ranges observed were 28 to 1690ng/L and 45 to 4156ng/L for glyphosate and AMPA, respectively with strong spatial and temporal fluctuations. Both contaminants were found at inbound sampling sites in the stream Muehlenfliess and concentrations decreased along the salinity gradient to the estuaries of the Baltic Sea. The data obtained in this study clearly depict the transport of glyphosate and AMPA to the Baltic Sea. Hence, detailed fate and risk assessment for both contaminants in marine environments are required.
اظهر المزيد [+] اقل [-]Modelling the fate of micropollutants in the marine environment using passive sampling النص الكامل
2015
Claessens, Michiel | De Laender, Frederik | Monteyne, Els | Roose, Patrick | Janssen, Colin R.
Polydimethylsiloxane sheets were used to determine freely dissolved concentrations (Cdiss) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the Belgian coastal zone. Equilibrium models were used to predict the whole water concentrations (Cww) of these compounds as well as their concentrations in sediment, suspended particulate matter (SPM) and biota. In general, contaminant concentrations were predicted well for whole water and biota. Cww was increasingly underpredicted as Koc increased, possibly because of the presence of black carbon. Concentrations in biota were overestimated by the equilibrium approach when logKow exceeded 6.5, suggesting an increasing role of transformation processes. Concentrations of PAHs and PCBs in sediment and SPM were consistently underpredicted although a good correlation between measured and predicted values was observed. This was potentially due to the use of experimental Koc values which have been found to underestimate partitioning of hydrophobic substances to sediment in field studies.
اظهر المزيد [+] اقل [-]Polybrominated diphenyl ethers in mussels (Mytilus galloprovincialis) collected from Central Adriatic Sea النص الكامل
2015
Piersanti, Arianna | Tavoloni, Tamara | Bastari, Eleonora | Lestingi, Carmela | Romanelli, Sara | Saluti, Giorgio | Moretti, Simone | Galarini, Roberta
One-hundred and thirty-four samples of mussels (Mytilus galloprovincialis) collected along Central Adriatic Sea in 2013 were examined to determine the levels of fifteen congeners of polybrominated diphenyl ethers (PBDEs). The purified samples were analysed by gas-chromatography coupled to tandem mass spectrometry (GC-MS/MS) applying the isotopic dilution. Only four congeners (PBDE 47, PBDE 99, PBDE 49 and PBDE 100) were present above the established limits of quantification with mean concentrations equal to 73, 30, 19 and 18pgg−1, respectively. The concentrations of PBDEs (sum) ranged from 27 to 386pgg−1, with the highest levels around the coastal area of Ancona town. The here found levels were comparable to those measured in mussels collected along Southern Adriatic Sea.
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