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291.
The measurement and induction of mixed function oxyigenases (MFOs) of limnetic gastropods were investigated to estimate their suitability as biomarkers. A determination of MFO activities was performed through the measurement of ethoxyresorufin-O-dealkylase (EROD), pentoxy-(PROD) and benzoxyresorufin-O-dealkylase-activity (BROD). Optimal measuring conditions of these activities were investigated in preparations of the digestive gland of 4 species of limnetic gastropods. Results indicate that MFO-activity inhibiting substances are accumulating in the microsomal pellet, the fraction commonly used for the measurement of MFO-activities. Therefore, the fraction used for induction studies was the postmitochondrial supernatant (PMS). EROD, PROD, and BROD activity ofPlanorbis planorbis andPlanorbis carinatus were measured after a treatment with Aroclor 1254 for 1–17 days. Maximal induction of EROD and PROD were 6 and 10 times the value in the control group ofP. carinatus, respectively induction inP. planorbis was lower. BROD-activity could not been measured inP. planorbis. InP. carinatus, BROD-activity increased to a maximum of 2 times after traetment with Aroclor 1254. The level of induction of EROD-activity is comparable to results described in analog studies with fish.  相似文献   
292.
Trace metal (Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals were observed in marine organisms with a predomination of Cu and Zn. The metal exposure levels exhibited obvious variations between species with the decreasing order of crab>shellfish>shrimp>fish. The higher metals enrichment seen in shellfish and crab species primarily attributed to their living habits and the higher sediment background values of trace metals. Endpoint bioaccumulation factor (BAFfd) was used to characterize the bioaccumulation potentials of marine organisms to trace metals, of which Cu and Zn were the most accumulated elements. The exposure of trace metals in the cultured organisms was far lower than those in wild marine organisms, which is probably due to the effect of growth dilution. Comparisons with previous studies demonstrated that the concentration profiles of most trace metals declined over the last one to two decades, except Cu, that increased indistinctively.  相似文献   
293.
Maritime transport has been playing a decisive role in global trade. Its contribution to the air pollution of the sea and coastal areas has been widely recognized. The air pollutant emission inventories of several harbors in China have already been established. However,the emission factors of local ships have not been addressed comprehensively, and thus are lacking from the emission inventories. In this study, on-board emission tests of eight diesel-powered offshore fishing ships were conducted near the coastal region of the northern Yellow Bo Sea fishing ground of Dalian, China. Results show that large amounts of fine particles( 0.5 μm, 90%) were found in maneuvering mode, which were about five times higher than those during cruise mode. Emission rates as well as emission factors based on both distance and fuel were determined during the cruise and maneuvering modes(including departure and arrival). Average emission rates and distance-based emission factors of CO, HC and PM were much higher during the maneuvering mode as compared with the cruise mode. However, the average emission rate of Nitrous Oxide(NOx) was higher during the cruise mode as compared with the maneuvering modes. On the contrary, the average distance-based emission factors of NOxwere lower during the cruise mode relative to the maneuvering mode due to the low sailing speed of the latter.  相似文献   
294.
The biological effects of contaminants in British estuaries and coastal waters have been studied for over 100 years. Until the 1970s. the major pollution impact on estuarine organisms was probably caused by poorly treated sewage which led to severe oxygen deficits and consequent asphyxiation of many water-breathers. However, since the introduction of improved sewage treatment in the last 30 years, a number of continuing impacts have come to light which represent true toxic effects of micro-contaminants. Sublethal changes observed in various bioassays and biomarkers are widespread in both fish and invertebrates, and in the most urbanised and industrialised estuaries, these effects are probably having impacts at the population and community levels. For example, there is good evidence to show that tributyltin from some antifouling paints has not only affected the sexuality and reproductive success of individual estuarine and coastal molluscs, but has also damaged some benthic communities of which molluscs are but a part. Although there are data to show that some contaminant concentrations are now declining, we do not yet have enough data in most cases to decide whether organisms have also begun to recover. This paper reviews the entire field of contaminant effects in UK estuarine and marine waters, focusing especially on the years 1985-2000, and makes some recommendations for future research and monitoring programmes.  相似文献   
295.
ABSTRACT

Marine spatial planning (MSP) has become the most adopted approach for sustainable marine governance. While MSP has transformative capacity, evaluations of its implementation illustrate large gaps between how it is conceptualised and how it is practiced. We argue that these gaps arise from MSP being implemented through post-political processes. Although MSP has been explored through post-political lenses, these evaluations are incomplete and do not provide sufficient detail about the complex nature of the post-political condition. Drawing on seminal literature, we conceptualise the post-political as consisting of highly interconnected modalities of depoliticisation, including: neoliberalism; choreographed participation; path dependency; technocratic-managerialism; and the illusion of progressive change. Using these modalities as an analytical framework, we evaluate English MSP and find that it focuses on entrenching neoliberal logic through: tokenistic participation; wholescale adoption of path-dependent solutions; obstructionist deployment of inactive technological solutions; and promising progressive change. We do not, however, view the post-political condition as unresolvable and we develop a suite of suggestions for the re-politicisation of MSP which, collectively, could form the basis for more radical forms of MSP.  相似文献   
296.
ABSTRACT

Although marine spatial planning (MSP) is increasingly being applied worldwide, it appears to be based on an ambiguity that has arisen from its dichotomous role of ensuring both conservation and development. This elusive ideal hints at a possible discrepancy between theory and practice. This paper explores the hypothesis that beyond a performative narrative, MSP is actually better described as a variety of devices which fulfil other roles and converge in terms of planning type. To test this hypothesis, this paper analyses the content of past and present MSP initiatives from around the world. The findings show that these initiatives view MSP either as a strategic sectoral spatial planning tool or strategic planning tool, brought in to complement existing initiatives. Furthermore, these two approaches can actually be seen to converge in the type of planning used, through the role attributed to spatial aspects, and more specifically in the place given to zoning. There are two key implications of these findings: the need to open up theoretical debates more broadly to different disciplinary perspectives on MSP; and the need for crucial choices to be made to ensure that MSP does not become an illusion behind which other agendas lie.

Highlights
  • Several scientific communities are working on MSP in parallel

  • MSP does not in reality fulfil its theoretical objectives, but it fulfils other roles

  • We make a critical review of 44 experiences of MSP from throughout the world

  • Different forms of MSP generally make similar uses of zoning

  • MSP is both illusory and necessary and must engage a critical turn

  相似文献   
297.
海上火车轮渡在国外得到了广泛的应用并取得了新进展,但在我国尚属空白。海上火车轮渡应是我国交通发展的方向之一。海上火车渡轮的航行安全是海上火车轮渡工程的关键问题。从船舶安全、装载货物安全、人员安全三方面,对影响渡轮航行安全的各因素进行了分析与论述,同时提出了相应的安全对策与措施  相似文献   
298.
In 1994 the Countryside Council for Wales, the government nature conservation and countryside advisor in Wales, published a consultation document on marine and coastal policy, and also commissioned research into the status of coastal zone management (CZM) in the Principality. The research, undertaken by the University of Wales Cardiff, investigated CZM from an international, national (U.K.) and Welsh perspective, concentrating on detailed case studies of three areas (including both urban and rural coasts). Policy makers, managers, practitioners and users from all sectors were included in the study which established current activity, identified problems and reviewe future plans. Interviews and questionnaire returns highlighted vital information gaps at all levels. These ranged fom a lack of basic data (including scientific and technical), to a breakdown in communication both within and between organisations, as well as a policy vacuum in both regional and central government.  相似文献   
299.
The stability of animal societies depends on individuals decisions about whether to tolerate or evict others and about whether to stay or leave. These decisions, in turn, depend on individuals costs and benefits of living in the group. The clown anemonefish, Amphiprion percula, lives in groups composed of a breeding pair and zero to four non-breeders. To determine why breeders accept the presence of non-breeders in this species I investigated the effect of non-breeders on multiple components of the breeders fitness. Non-breeders did not assist breeders in any obvious way. Experimental removal of non-breeders had no significant effect on the survival, growth, or reproductive success of breeders. Experimental removal of one of the breeding pair showed that non-breeders had little effect on the time taken for a widowed breeder to recommence breeding. The results indicate that the presence of non-breeders neither enhances, nor reduces, the fitness of breeders in A. percula. I suggest that non-breeders might modulate their effect on the fitness of breeders, either by reducing the costs they inflict or by increasing the benefits they provide, such that it just pays breeders to tolerate, rather than to evict, them. This study illustrates that animal societies can be stable even when some individuals gain nothing from the association.Communicated by M. Abrahams  相似文献   
300.
The Irish Sea’s distinctive hydrographic features present unique opportunities for research into the complex processes that regulate shelf-sea ecosystems. Such studies are essential in developing capabilities to detect and evaluate change in marine environments. A 1993 review showed almost 230 projects underway on the Irish Sea, spanning all the major fields of marine science. But a large proportion of research projects failed to indicate the purpose of the work; overall, there was a remarkable absence of clarity and specificity in the objectives. Progress in some fields is also hampered by insufficient coordination and cohesion; at present there are no standing arrangements between Ireland and the United Kingdom that provide for bilateral co-ordination of scientific work in the area. There is clearly a need for a more planned and integrated Irish Sea science programme to provide information for management purposes and also to advance scientific understanding of the components and functions of Irish Sea ecosystems, and how and why they change with time. There is a common belief that the first of these predominantly involves monitoring, and the second research. However, the paper cautions that this is a dubious and unnecessary distinction. A strategy aimed at better integration of research and monitoring (e.g. a framework of linked objectives and targets) could substantially increase the information dividend from current investments in Irish Sea science. Based on a joint Irish/UK review, this paper outlines studies and approaches that are seen as key elements of a future, more relevant and cost-effective research programme for the Irish Sea.  相似文献   
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