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981.
This paper is an attempt to synthesize and briefly examine the causes of the marine fisheries crisis, and to speculate about future initiatives. Ultimately, the human appetite is at the root of the marine fisheries crisis. But religion, technology, population pressure, science and our economic systems have provided vehicles for human appetite and thus contributed to overfishing. These various topics are further discussed in the context of the potential restoration of marine fisheries populations. All titles with gratitude to The Talking Heads. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
982.
The large number of radio frequency (RF) transmitters employed in modern marine platforms requires that they operate in mutual coexistence while posing no danger to operators and equipment despite the limited available physical space. A key to the successful system integration is the control of the electromagnetic environment on the ships’ topsides, which might pose radiation hazards (RADHAZ) to personnel (HERP). HERP are caused by transmitter antenna installations that generate intentional EM radiation in excess of the safe levels in zones of personnel activity. Radiation safety to personnel is achieved when the average radiation power density is below the permissible exposure limits (PEL) for HERP at locations of personnel activity and medical equipment operation. This paper describes the analysis tools and techniques for the evaluation of HERP on marine platforms. The same approaches could be employed in the analysis of land site antenna deployment scenarios.  相似文献   
983.
三峡库区船舶污染及综合防治对策研究   总被引:5,自引:0,他引:5  
三峡大坝建成后,将形成一个长662.9km,面积1045km^2的巨型水库,水库的蓄水会使库区水体的稀释自净能力降低。而目前重庆市辖区内船舶总数已达6000艘左右,旅客日均流量在6万人左右。船舶含油污水、生活污水、船舶垃圾等对库区水质造成破坏:其中油类排放量将为5694t/a,CODcr为1533t/a,BOD5为766.5t/a,SS为1840t/a,生活垃圾为5000t/a,会严重影响整个三峡库区水生态系统。近年来虽然国家重点执行对船舶油污水排放实行控制,船舶垃圾进行接收处理等多项措施,但据调查,随着航运业的发展,现有船舶污染治理主要还在管理、宣传、执法、港口设施、船舶设备更新等7个方面存在问题,船舶对库区水环境的污染日趋严惩。为避免船舶对库区水域的污染,除对库区航运规模、船舶数量和作总量控制外,还从资金、机构建设、设施建设、环保执法、船舶设备更新等方面提出了综合防治对策,使因船舶排放污染物对库区水域造成的污染减少到最低程度,确保三峡库区水污染整治规划目标的早日实现。  相似文献   
984.
There is still a long-term debate concerning the relative contributions of naturally emitted and anthropogenic Se at the regional and local scales. Here, Se and heavy metal concentrations are reported for epiphytic lichens collected in coastal and inland areas from the USA, Canada and France for assessing atmospheric Se source. Correlations found between Se and Cl in lichens confirmed the major marine biogenic source for atmospheric Se. Continental samples do not show systematic relationships between Se and other metal (Pb, Cu, In …) contents, even for lichens collected in the vicinity of smelters or close to urban areas. Our results suggest that, although anthropogenic Se may be present, the marine biogenic Se source is a major contributor to atmospheric Se for our sampling locations. The contribution of naturally emitted atmospheric Se may be significant in urban and industrial areas and should be taken into account for further studies.  相似文献   
985.
Increased development pressures on the marine environment and the potential for multiple use conflicts, arising as a result of the current expansion of offshore wind energy, fishing and aquaculture, dredging, mineral extraction, shipping, and the need to meet international and national commitments to biodiversity conservation, have led to increased interest in sea use planning with particular emphasis on marine spatial planning. Several European countries, on their own initiative or driven by the European Union's Marine Strategy and Maritime Policy, the Bergen Declaration of the North Sea Conference, and the EU Recommendation on Integrated Coastal Zone Management, have taken global leadership in implementing marine spatial planning. Belgium, The Netherlands, and Germany in the North Sea, and the United Kingdom in the Irish Sea, have already completed preliminary sea use plans and zoning proposals for marine areas within their national jurisdictions. This paper discusses the nature and context of marine spatial planning, the international legal and policy framework, and the increasing need for marine spatial planning in Europe. In addition, the authors review briefly three marine spatial planning initiatives in the North Sea and conclude with some initial lessons learned from these experiences.  相似文献   
986.
987.
The distribution and behaviour of the natural-series alpha-emitter polonium-210 in the marine environment has been under study for many years primarily due to its enhanced bioaccumulation, its strong affinity for binding with certain internal tissues, and its importance as a contributor to the natural radiation dose received by marine biota as well as humans consuming seafoods. Results from studies spanning nearly 5 decades show that 210Po concentrations in organisms vary widely among the different phylogenic groups as well as between the different tissues of a given species. Such variation results in 210Po concentration factors ranging from approximately 103 to over 106 depending upon the organism or tissue considered. 210Po/210Pb ratios in marine species are generally greater than unity and tend to increase up the food chain indicating that 210Po is preferentially taken up by organisms compared to its progenitor 210Pb. The effective transfer of 210Po up the food chain is primarily due to the high degree of assimilation of the radionuclide from ingested food and its subsequent strong retention in the organisms. In some cases this mechanism may lead to an apparent biomagnification of 210Po at the higher trophic level. Various pelagic species release 210Po and 210Pb packaged in organic biodetrital particles that sink and remove these radionuclides from the upper water column, a biogeochemical process which, coupled with scavenging rates of this radionuclide pair, is being examined as a possible proxy for estimating downward organic carbon fluxes in the sea. Data related to preferential bioaccumulation in various organisms, their tissues, resultant radiation doses to these species, and the processes by which 210Po is transferred and recycled through the food web are discussed. In addition, the main gaps in our present knowledge and proposed areas for future studies on the biogeochemical behaviour of 210Po and its use as a tracer of oceanographic processes are highlighted in this review.  相似文献   
988.
The determination of 210Po and 210Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10−1 Bq kg−1 (wet wt.) in jellyfish, to very high values of about of 3 × 104 Bq kg−1 (wet wt.) in the gut walls of sardines, with a common pattern of 210Po > 210Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that 210Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As 210Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, 210Po transfer factors are similar to ecotrophic coefficients. 210Pb is transferred less efficiently in marine food chains and this contributes to increased 210Po:210Pb activity ratios in some trophic levels.  相似文献   
989.
The significance of metal concentrations in marine mammals is not well understood and relating concentrations between stranded and free-ranging populations has been difficult. In order to predict liver concentrations in free-ranging dolphins, we examined concentrations of trace elements (Al, As, Ba, Be, Cd, Co, Cu, Fe, Li, Mn, Ni, Pb, Sb, Se, Sn, total Hg (THg), V, Zn) in skin and liver of stranded bottlenose dolphins (Tursiops truncatus) from the South Carolina (SC) coast and the Indian River Lagoon, Florida (FL) during 2000-2008. Significantly higher concentrations of Zn, Fe, Se, Al, Cu and THg were found in skin while liver exhibited significantly higher Cu, Fe, Mn and THg concentrations for both study sites. Mean skin concentrations of Cu and Mn were significantly higher in SC dolphins while higher concentrations of THg and V were found in FL dolphins. In addition, liver tissues in SC dolphins exhibited significantly higher As concentrations while higher Fe, Pb, Se, THg, and V levels were found in FL dolphins. Two elements (Cu and THg) showed significant age-related correlations with skin concentration while five elements (Cu, Se, THg, Zn and V) showed age-related correlations with liver concentrations. Geographic location influenced age-related accumulation of several trace elements and age-related accumulation of THg in hepatic tissue was observed for both sites to have the highest correlations (r2 = 0.90SC; r2 = 0.69FL). Mean THg concentration in liver was about 10 times higher in FL dolphins (330 μg g−1 dw) than those samples from SC dolphins (34.3 μg g−1 dw). The mean molar ratio of Hg to Se was 0.93 ± 0.32 and 1.08 ± 0.38 for SC and FL dolphins, respectively. However, the Hg:Se ratio varied with age as much lower ratios (0.2-0.4) were found in younger animals. Of the 18 measured elements, only THg was significantly correlated in skin and liver of stranded dolphins and skin of free-ranging dolphins from both sites suggesting that skin may be useful in predicting Hg concentrations in liver tissue of free-ranging dolphins. Results indicate that 33% of the stranded and 15% of the free-ranging dolphins from FL exceed the minimum 100 μg g−1 wet weight (ww) (∼400 dw) Hg threshold for hepatic damage while none from SC reached this level. Hepatic concentrations of As in SC dolphins and V in FL dolphins were also highly correlated with skin concentrations which may have some regional specificity predictive value. The present study provides the first application of trace element concentrations derived from stranded bottlenose dolphins to predict liver concentrations in free-ranging populations.  相似文献   
990.
This paper aims to contribute to the current debate on Marine Spatial Planning (MSP) by exploring the issue of stakeholder engagement. MSP is an emergent policy field that is subject to an increasing body of research, yet the role, scope and nature of participatory engagement within the process remains a neglected topic. This paper briefly reviews the nature of the ‘marine problem’, to which MSP is seen to be the response and describes the emergence of MSP policy in the UK with specific emphasis on participatory aspects. Drawing on the experience of terrestrial planning it discusses the potential benefits of stakeholder engagement in MSP and highlights some of the key issues that need to be taken into account when shaping stakeholder input into the process. It then goes on to describe the findings from a series of interviews with key stakeholders in the Irish Sea Region, which suggest that we need to develop a more critical and deeper understanding of how various interests frame the ‘marine problem’, and how they see their role in shaping the form of the MSP process. This highlights the importance of encouraging stakeholder involvement in MSP, the need to develop a shared vision of a ‘sea interest’. Priorities are then set for research to support this important policy agenda.  相似文献   
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