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1.
Organotins, especially tributyltins (TBT) are highly toxic to many marine organisms. These compounds are introduced in marine waters by ship trafficking, ship scrapping activities, as antifouling compounds and sewage disposal. Marine fishes, crustaceans and molluscans are easily prone to organotins contamination. In view of this, a baseline monitoring study was conducted in order to establish the levels of organotins in edible marine fishes, bivalves, shrimps, squids and crabs collected from Mumbai, Goa and Karwar on the west coast of India. At these locations average organotin concentration found in fishes, clams, shrimps, squids and crabs was 108, 852, 179, 70 and 89 ng Sn g−1 dw, respectively. In all the samples butyltins dominated over phenyltins. The levels of organotins suggest that all the organisms were contaminated with organotins and their consumption may pose health problems to humans. 相似文献
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The global economy is currently experiencing one of its biggest contractions on record. A sharp decline in global imports and exports since 2008 has affected global merchant vessel traffic, the principal mode of bulk commodity transport around the world. During the first quarter of 2009, 10% and 25% of global container and refrigerated vessels, respectively, were reported to be unemployed. A large proportion of these vessels are lying idle at anchor in the coastal waters of South East Asia, sometimes for periods of greater than 3 months. Whilst at anchor, the hulls of such vessels will develop diverse and extensive assemblages of marine biofouling species. Once back in service, these vessels are at risk of transporting higher-than-normal quantities of marine organisms between their respective global trading ports. We discuss the potential ramifications of the global economic crisis on the spread of marine non-indigenous species via global commercial shipping. 相似文献
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Catherine Lalande Alexandre Forest David G. Barber Yves Gratton Louis Fortier 《Continental Shelf Research》2009
The ongoing regression of sea ice cover is expected to significantly affect the fate of organic carbon over the Arctic continental shelves. Long-term moored sediment traps were deployed in 2005–2006 in the Beaufort Sea, Northern Baffin Bay and the Laptev Sea to compare the annual variability of POC fluxes and to evaluate the factors regulating the annual cycle of carbon export over these continental shelves. Annual POC fluxes at 200 m ranged from 1.6 to 5.9 g C m−2 yr−1 with the highest export in Northern Baffin Bay and the lowest export over the Mackenzie Shelf in the Beaufort Sea. Each annual cycle exhibited an increase in POC export a few weeks before, during, or immediately following sea ice melt, but showed different patterns over the remainder of the cycle. Enhanced primary production, discharge of the Lena River, and resuspension events contributed to periods of elevated POC export over the Laptev Sea slope. High POC fluxes in Northern Baffin Bay reflected periods of elevated primary production in the North Water polynya. In the Beaufort Sea sediment resuspension contributed to most of the large export events. Our results suggest that the outer shelf of the Laptev Sea will likely sustain the largest increase in POC export in the next few years due to the large reduction in ice cover and the possible increase in the Lena River discharge. The large differences in forcing among the regions investigated reinforce the importance of monitoring POC fluxes in the different oceanographic regimes that characterize the Arctic shelves to assess the response of the Arctic Ocean carbon cycle to interannual variability and climate change. 相似文献
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Summary Two methods of the evaluation of sensible heat flux are briefly presented from the view point of their application to micrometeorology. The comparison of sensible fluxes for coastal and inland stations is presented, in order to explain the influence of the marine atmosphere on these fluxes. They reach a maximum value in summer at the coastal stations, due to maximum wind speed and high convective activity developed by the influence of the marine atmosphere. 相似文献
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This paper presents some statistical evaluations of the surface energy and soil water balance fluxes, for a prairie-type canopy, using the Earth model with a double-reservoir system for the management of the soil water reserve and the regulation of actual evapotranspiration. The mean values of these fluxes are estimated from energy and water balance simulations done on a 30-year climatic reference period (1951-1980). From values of these fluxes calculated for each meteorological synoptic station, mappings of net radiation, actual evapotranspiration, drainage and conduction fluxes have been made over French territory. Lastly, a few conclusions pertaining to the spatial variability of fluxes and to the partition of rainfall between run-off and drainage on the one hand and replenishment of the soil water reserve on the other hand are drawn from these preliminary results. 相似文献
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The fate of linear alkylbenzenesulponates (LAS) in estuaries and coastal areas of the North Sea has been characterized with simple environmental models. The predicted concentration range in the estuaries around the North Sea (0.9-9 microg LAS l(-1)) was validated by monitoring data (1-9 microg LAS l(-1)). In offshore sites of the North Sea, it is estimated--and experimentally verified for a few sites--that the LAS concentration is below analytical detection limit (i.e., 0.5 microg LAS l(-1)). The effects of LAS on marine organisms have been reviewed. For short-term acute tests, there was no significant difference (p = 0.83) between the mean LC50 values of freshwater and marine organisms (mainly pelagic species tested, 4.1 and 4.3 mg LAS l(-1), respectively). For longer-term chronic tests, it appeared that the sensitivity (mean no-observed effect concentration (NOEC) value) of marine and freshwater organisms (0.3 and 2.3 mg LAS l(-1), respectively) was significantly different pt-test = 0.007). The predicted no-effect-concentrations (PNEC) were 360 and 31 microg LAS l(-1), for freshwater and marine pelagic communities, respectively. Given that the maximum expected estuarine and marine concentrations are 3 to > 30 times lower than the PNEC, the risk of LAS to pelagic organisms in these environments is judged to be low. 相似文献
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A.W. Morris 《Marine pollution bulletin》1974,5(4):54-59
Many surveys of trace contaminants of seawater are based on the supposition that the situation is static. Little is known about seasonal fluctuations in the concentrations of these contaminants and less about the cause of this variation. Fluctuation in freshwater carrying metals or sediment that will trap contaminants, changes in movements of water masses in the sea, as well as the use of trace metals by marine organisms, are all contributory factors. 相似文献
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在TOGA－COAREIOP期间用涡度相关法对海气热通量进行了船载直接观测．对垂直风速、温度和湿度湍流脉动观测数据的谱分析显示它们在高频区基本满足"－2／3次方律"．对船体简谐震荡影响的讨论从理论上证明该影响在热通量计算中可被忽略．根据以此方法得到的通量求出了中性层结条件下感热和潜热的整体输送系数分别为2．25×10－3和1．26×10－3．对海气边界层特性的分析表明该海域的近海层主要呈中性或弱不稳定层结．海气通量的变化与背景环流形势密切相关,潜热通量主要受海面风场强度的影响,而感热通量变化除了风场的影响外,层结变化也是一个重要因素．用整体输送法计算TOGA－COAREIOP期间以及TOGA期间8个航次的通量结果而得到的Bowen比约为0．1,显示潜热通量是暖池大气的主要热源． 相似文献
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O. G. Mironov 《洁净——土壤、空气、水》1988,16(3):269-280
Sea entered pollutions, in particular oil and oil products, interact complexly with marine biota. On the one hand, oil causes disfunction of marine communities, death of some marine representatives and sometimes of the whole community. On the other hand, marine organisms and their communities transform pollutions during purification processes improving marine environment quality. It is known, that under pollution conditions the number of aquarium-inhabiting organisms is reduced and only the most resistable species are left. The study of such species opens perspectives for the creation of hydrobiological systems and their purposeful use in cleaning polluted waters and sanitation of coastal aquaria. 相似文献
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A global ocean circulation model is coupled to a particle-tracking model to simulate the transport of floating debris washed into the North Pacific Ocean by the Tohoku tsunami. A release scenario for the tsunami debris is based on coastal population and measured tsunami runup. Archived 2011/2012 hindcast current data is used to model the transport of debris since the tsunami, while data from 2008 to 2012 is used to investigate the distribution of debris on timescales up to 4 years. The vast amount of debris pushed into ocean likely represents thousands of years worth of ‘normal’ litter flux from Japan’s urbanized coastline. This is important since a significant fraction of the debris will be comprised of plastics, some of which will degrade into tiny particles and be consumed by marine organisms, thereby allowing adsorbed organic pollutants to enter our food supply in quantities much higher than present. 相似文献
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Derelict fishing nets in Puget Sound and the Northwest Straits: Patterns and threats to marine fauna
Derelict fishing gear remains in the marine environment for years, entangling, and killing marine organisms worldwide. Since 2002, hundreds of derelict nets containing over 32,000 marine animals have been recovered from Washington’s inland waters. Analysis of 870 gillnets found many were derelict for years; most were recovered from northern Puget Sound and high-relief rocky habitats and were relatively small, of recent construction, in good condition, stretched open, and in relatively shallow water. Marine organisms documented in recovered gillnets included 31,278 invertebrates (76 species), 1036 fishes (22 species), 514 birds (16 species), and 23 mammals (4 species); 56% of invertebrates, 93% of fish, and 100% of birds and mammals were dead when recovered. For all taxa, mortality was generally associated with gillnet effectiveness (total area, age and condition, and suspension in the water). Mortality from derelict fishing gear is underestimated at recovery and may be important for species of economic and conservation concern. 相似文献
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ShaoHua Zhao ZhiFei Liu Quan Chen XingXing Wang JiangNan Shi HaiYan Jin JingJing Liu ZhiMin Jian 《中国科学:地球科学(英文版)》2017,60(7):1368-1381
Sediment components and their fluxes of Cores MD12-3428(water depth: 903 m), MD12-3433(water depth: 2125 m),and MD12-3434(water depth: 2995 m), obtained along a transect on the continental slope of the northern South China Sea, have been conducted to reveal the spatiotemporal variations and the controlling factors of the sediment components and of their fluxes.Results show that deep-sea sediments in the northern South China Sea are composed mainly of terrigenous(59–89%) and carbonate(6–38%) particles, with minor components of opal(1.6–9.4%) and organic matter(0.7–1.9%). Fluxes of terrigenous and carbonate particles reach up to 2.4–21.8 and 0.4–6.5 g cm–2 kyr–1, respectively, values that are one to two orders of magnitude higher than the fluxes of opal and organic matter. Temporal variations of the percentages and fluxes of deep-sea sediment components have displayed clear glacial-interglacial cyclicity since the last glaciation. Terrigenous, opal, and organic matter percentages and their fluxes increas clearly during marine isotope stage 2, while carbonate percentages and fluxes show an opposite variation pattern or are characterized by an unremarkable increase. This implies that deep-sea carbonate in the South China Sea is affected by the dilution of terrigenous inputs during the sea-level lowstand. With increasing water depth along the transect, the terrigenous percentage increases but with largely decreased fluxes. Both the percentage and flux of carbonate decrease, while the percentages and fluxes of opal and organic matter display much more complicated variational features. The spatiotemporal variations of deep-sea sediment components and of their fluxes since the last glaciation in the northern South China Sea are strongly controlled by sea-level fluctuations. Simultaneously, terrigenous supply associated with monsoonal rainfall, marine primary productivity,and the dilution effect between terrigenous and biogenic particles, also play interconnected roles in the sediment accumulation processes. 相似文献
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C Geels J.H Christensen L.M Frohn J Brandt 《Physics and Chemistry of the Earth》2002,27(35):1495-1505
A three-dimensional Eulerian nested model for transport, diffusion, and surface fluxes of CO2 has been developed. The model is used to study the spatial and temporal variations of atmospheric CO2 concentrations as a step towards a better understanding of the regional source pattern over Europe. The influence from the national surface characteristics, as e.g. fossil CO2 emissions or ecosystem fluxes, can be treated on a continental or national level in the model. In the future the model can be used as a mean to corroborate national and EU-wide controls or reductions of carbon emissions. One of the major questions in the estimation of e.g. national CO2 budgets is the quantification of surface ecosystem fluxes. In order to test the sensitivity of atmospheric CO2 concentrations to ecosystem fluxes, two different parameterizations [J. Geophys. Res. 92 (1987) 2999] and [Global Biogeochem. Cycles 10 (1996) 269] have been implemented in the model. The model both with and without nest is validated by comparison with measurements and the different model results will be discussed. The results show that including a nested domain with higher spatial resolution significantly improves the model performance in some areas. In spite of regional deviations in the two sets of ecosystems fluxes no major differences are seen over Europe as a whole when either of the two parameterizations are included in the model and the results compared. 相似文献
16.
Influence of the biomass content in sediment on the sediment nutrient flux for a pulsed organic load
A laboratory study was carried out to investigate the influence of the biomass content in the sediment on the rate of diagenesis of particulate organic materials (POM) and the consequent sediment oxygen demand (SOD) and nutrient fluxes. Fish food pellets were loaded into the sediment to simulate a sudden POM input. Three types of sediments with different biomass contents were tested, including a raw marine sediment, the marine sediment after one month of cultivation and an artificial sediment of sand and clay without any biomass. There was little difference in organic flux from the three different sediments. However, compared to the artificial sediment, the marine sediments had much higher SOD and ammonia flux. A mathematical model also has been developed for the SOD dynamics and nutrient fluxes. Both the experimental and simulation results indicate the important role of the biomass in the sediment in POM diagenesis, SOD and nutrient fluxes. 相似文献
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Influence of the biomass content in sediment on the sediment nutrient flux for a pulsed organic load
《Marine pollution bulletin》2009,58(6-12):681-688
A laboratory study was carried out to investigate the influence of the biomass content in the sediment on the rate of diagenesis of particulate organic materials (POM) and the consequent sediment oxygen demand (SOD) and nutrient fluxes. Fish food pellets were loaded into the sediment to simulate a sudden POM input. Three types of sediments with different biomass contents were tested, including a raw marine sediment, the marine sediment after one month of cultivation and an artificial sediment of sand and clay without any biomass. There was little difference in organic flux from the three different sediments. However, compared to the artificial sediment, the marine sediments had much higher SOD and ammonia flux. A mathematical model also has been developed for the SOD dynamics and nutrient fluxes. Both the experimental and simulation results indicate the important role of the biomass in the sediment in POM diagenesis, SOD and nutrient fluxes. 相似文献
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Photochemical degradation of phenanthrene as a function of natural water variables modeling freshwater to marine environments 总被引：1，自引：0，他引：1
Photolysis rates of phenanthrene as a function of ionic strength (salinity), oxygen levels and humic acid concentrations were measured in aqueous solution over the range of conditions found in fresh to marine waters. Photolysis followed first order kinetics, with an estimated photodegradation half-life in sunlight in pure water of 10.3±0.7h, in the mid-range of published results. Photolysis rate constants decreased by a factor of 5 in solutions with humic acid concentrations from 0 to 10 mg C L(-1). This decrease could be modeled entirely based on competitive light absorption effects due to the added humics. No significant ionic strength or oxygen effects were observed, consistent with a direct photolysis mechanism. In the absence of significant solution medium effects, the photodegradation lifetime of phenanthrene will depend only on solar fluxes (i.e. temporal and seasonal changes in sunlight) and not vary with a freshwater to marine environment. 相似文献
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The low-level radioactive liquid wastes which arise at the U.K. nuclear fuel reprocessing plant at Windscale on the Cumbria coast are discharged into the Irish Sea. These wastes are initially dispersed but they can also become reconcentrated in marine organisms. The present work discusses the concentrations of 137Cs relative to those of potassium in the various stages of marine food chains and shows that discrimination occurs in favour of 137Cs over potassium during the transfer between the different trophic levels. 相似文献
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The impacts of pollution on marine organisms are often investigated using the viability of their haemocytes. Although this assay is routinely used in monitoring, field and laboratory experimentation, there has been less effort in further optimizing procedures to reduce artefacts and facilitate sampling over large geographic areas. 相似文献