细化搜索
结果 701-710 的 2,512
Emerging organic contaminants in coastal waters: Anthropogenic impact, environmental release and ecological risk 全文
2014
Jiang, Jheng-Jie | Lee, Chon-Lin | Fang, Meng-Der
This study provides a first estimate of the sources, distribution, and risk presented by emerging organic contaminants (EOCs) in coastal waters off southwestern Taiwan. Ten illicit drugs, seven nonsteroidal anti-inflammatory drugs (NSAIDs), five antibiotics, two blood lipid regulators, two antiepileptic drugs, two UV filters, caffeine, atenolol, and omeprazole were analyzed by solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry (SPE–LC–MS/MS). Thirteen EOCs were detected in coastal waters, including four NSAIDs (acetaminophen, ibuprofen, ketoprofen, and codeine), three antibiotics (ampicillin, erythromycin, and cefalexin), three illicit drugs (ketamine, pseudoephedrine, and MDMA), caffeine, carbamazepine, and gemfibrozil. The median concentrations for the 13 EOCs ranged from 1.47ng/L to 156ng/L. Spatial variation in concentration of the 13 EOCs suggests discharge into coastal waters via ocean outfall pipes and rivers. Codeine and ampicillin have significant pollution risk quotients (RQ>1), indicating potentially high risk to aquatic organisms in coastal waters.
显示更多 [+] 显示较少 [-]New insights on the role of sea ice in intercepting atmospheric pollutants using 129I 全文
2014
Gómez-Guzmán, J.M. | Cámara-Mor, P. | Suzuki, T. | López-Gutiérrez, J.M. | Mas, J.L. | Masqué, P. | Moran, S.B. | Smith, J.N.
Measurements of 129I carried out on sea ice samples collected in the central Arctic Ocean in 2007 revealed relatively high levels in the range of 100–1400×107 at L−1 that are comparable to levels measured in the surface mixed layer of the ocean at the same time. The 129I/127I ratio in sea ice is much greater than that in the underlying water, indicating that the 129I inventory in sea ice cannot be supported by direct uptake from seawater or by iodine volatilization from proximal (nearby) oceanic regimes. Instead, it is proposed that most of the 129I inventory in the sea ice is derived from direct atmospheric transport from European nuclear fuel reprocessing plants at Sellafield and Cap La Hague. This hypothesis is supported by back trajectory simulations indicating that volume elements of air originating in the Sellafield/La Hague regions would have been present at arctic sampling stations coincident with sampling collection.
显示更多 [+] 显示较少 [-]High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas) 全文
2014
Antunes, R. | Kvadsheim, P.H. | Lam, F.P.A. | Tyack, P.L. | Thomas, L. | Wensveen, P.J. | Miller, P.J.O.
The potential effects of exposing marine mammals to military sonar is a current concern. Dose–response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1–2kHz and 6–7kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose–response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170dB re 1μPa, SELcum=173dB re 1μPa2s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose–response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources.
显示更多 [+] 显示较少 [-]Linking the toxic metals to benthic community alteration: A case study of ecological status in the Bohai Bay 全文
2014
Wu, Bin | Song, Jinming | Li, Xuegang
Ecological effects and quality status of sediments in the Bohai Bay (North China) were studied by incorporating the traditional chemical analysis and benthic community structure. In the present study, paired sediments from 20 stations were sampled for chemical analysis and benthic assemblages. The overall results demonstrated that sediment impairment mainly appeared in the southern part of the Bay. The results obtained from the principal component analysis regarding benthic data and potential explanatory factors indicated that As, Hg and petroleum hydrocarbons (PHs) were responsible for the distribution of macrofaunal assemblages. Canonical correspondence analysis further showed As was significantly correlated to the benthic alteration, which provided evidence of ecological relevance to chemical substances of concern. Overall, this study revealed the metal contamination in the Bohai Bay was not as severe as previously regarded. Yet, further investigation is still needed considering the complexity of sediment matrices.
显示更多 [+] 显示较少 [-]Spatial variation, environmental assessment and source identification of heavy metals in sediments of the Yangtze River Estuary 全文
2014
Wang, Jiawei | Liu, Ruimin | Zhang, Peipei | Yu, Wenwen | Shen, Zhenyao | Feng, Chenghong
In order to analyze the spatial distribution patterns, pollution sources and ecological risks of heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn), 30 sediment samples were taken from in the Yangtze River Estuary (YRE). The results indicated that the contamination ranking of heavy metals was As>Cr>Cd>Ni>Mn>Pb>Zn>Cu. In the various areas, the pollution magnitude decreased as follows: adjacent sea>river mouth>inner-region. Compared to data published for other regions, the YRE data indicated that the sediment was not severely contaminated by heavy metals. In the YRE, natural and anthropogenic inputs dominated the distribution patterns of the heavy metals. Beyond that, the hydrodynamic conditions, such as the Taiwan warm current, coastal current and Yangtze diluted water, also caused distribution variations in the study areas.
显示更多 [+] 显示较少 [-]Bioaccumulation of trace elements in dominant mesozooplankton group inhabiting in the coastal regions of Indian Sundarban mangrove wetland 全文
2014
Bhattacharya, Bhaskar Deb | Hwang, Jiang-Shiou | Tseng, Li-Chun | Sarkar, Santosh Kumar | Rakshit, Dibyendu | Mitra, Soumita
Mesozooplankton (Body size 20–200μm) along with the surface water were collected from coastal regions of Sundarban, northeastern part of Bay of Bengal considering three seasons, namely premonsoon, monsoon and postmonsoon. Samples were analyzed for community structure and the dominant copepod species were further analyzed for trace metal concentration. In total, 50 copepods were identified (22 families and 43 genera). The dominant mesozooplankton species included 9 copepods and an epipelagic chaetognath, exhibited both spatial and seasonal variations. Metal concentration exhibited considerable inter-specific variations for the copepods and the mean concentrations were: Fe, 1350.2–51118.3μg/g; Al, 647.2–73019.1μg/g; Ni, 32.4–110.3μg/g; Mn, 122.8–1066.5μg/g; Pb, 0.04–97.5μg/g; Pb, 10.6–97.5μg/g; Cd, 4.2–21.6μg/g; Cu, 17.4–145.1μg/g; Zn, 225.7–1670.9μg/g; Cr, 21.7–194.3μg/g; Co, 1.32–111.1μg/g. Metal concentrations showed the following order: Sagitta bedoti>Coryceas danae>Oithona sp.>Eucalanus subcrassus>Labidocera euchaeta>Paracalanus parvus>Acartiella tortaniformis>Acartia spinicauda>Pseudocalanus serricaudatus.
显示更多 [+] 显示较少 [-]Detection of Helicobacter pylori in the coastal waters of Georgia, Puerto Rico and Trinidad 全文
2014
Holman, Chelsea B. | Bachoon, D.S. | Otero, Ernesto | Ramsubhag, Adesh
Fecal pollution in the coastal marine environments was assessed at eleven sampling locations along the Georgia coast and Trinidad, and nine sites from Puerto-Rico. Membrane filtration (EPA method 1604 and method 1600) was utilized for Escherichia coli and enterococci enumeration at each location. Quantitative polymerase chain reaction (qPCR) amplification of the 16S ribosomal RNA gene was used to determine the presence of the Helicobacter pylori in marine samples. There was no significant correlation between the levels of E. coli, enterococci and H. pylori in these water samples. H. pylori was detected at four of the 31 locations sampled; Oak Grove Island and Village Creek Landing in Georgia, Maracas river in Trinidad, and Ceiba Creek in Puerto Rico. The study confirms the potential public health risk to humans due to the widespread distribution of H. pylori in subtropical and tropical costal marine waters.
显示更多 [+] 显示较少 [-]Growth, nutrient status, and photosynthetic response to diesel-contaminated soil of a cordgrass, Spartina argentinensis 全文
2014
Redondo-Gómez, Susana | Petenello, María C. | Feldman, Susana R.
The present study was conduced to investigate the tolerance limits of Spartina argentinensis, which occurs in inland marshes of the Chaco-Pampean regions of Argentina, to diesel-contaminated soil. A glasshouse experiment was designed to investigate the effect of diesel fuel from 0% to 3% on growth and photosynthetic apparatus of S. densiflora by measuring gas exchange and photosynthetic pigments. We also performed chemical analysis of plant samples, and determined mycorrhizal index. Tiller and root biomasses declined with increasing diesel fuel concentration, as well as photosynthetic rate (A). Reductions in A could be accounted for by non-stomatal limitations. Mycorrhizal roots of S. argentinensis were reduced by the presence of diesel fuel, but did not affect its nutritional status; in fact, most element concentrations increased with diesel contamination. Despite the negative effect of diesel-contaminated soil, S. argentinensis continued growing, which could be useful management options for phytorremediation of diesel-contaminated soils.
显示更多 [+] 显示较少 [-]Coral reef baselines: How much macroalgae is natural? 全文
2014
Bruno, John F. | Precht, William F. | Vroom, Peter S. | Aronson, Richard B.
Identifying the baseline or natural state of an ecosystem is a critical step in effective conservation and restoration. Like most marine ecosystems, coral reefs are being degraded by human activities: corals and fish have declined in abundance and seaweeds, or macroalgae, have become more prevalent. The challenge for resource managers is to reverse these trends, but by how much? Based on surveys of Caribbean reefs in the 1970s, some reef scientists believe that the average cover of seaweed was very low in the natural state: perhaps less than 3%. On the other hand, evidence from remote Pacific reefs, ecological theory, and impacts of over-harvesting in other systems all suggest that, historically, macroalgal biomass may have been higher than assumed. Uncertainties about the natural state of coral reefs illustrate the difficulty of determining the baseline condition of even well studied systems.
显示更多 [+] 显示较少 [-]Transforming management of tropical coastal seas to cope with challenges of the 21st century 全文
2014
Sale, Peter F. | Agardy, Tundi | Ainsworth, Cameron H. | Feist, Blake E. | Bell, Johann D. | Christie, Patrick | Hoegh-Guldberg, Ove | Mumby, P. J. (Peter J.) | Feary, David A. | Saunders, Megan I. | Daw, Tim M. | Foale, Simon J. | Levin, Phillip S. | Lindeman, Kenyon C. | Lorenzen, Kai | Pomeroy, R. S. (Robert S.) | Allison, Edward H. | Bradbury, R.H. | Corrin, Jennifer | Edwards, Alasdair J. | Obura, David O. | Sadovy de Mitcheson, Yvonne J. | Samoilys, Melita A. | Sheppard, Charles R.C.
Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge – one that affects the lives of one fifth of humanity.
显示更多 [+] 显示较少 [-]