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Responses of a Mediterranean soft bottom community to short-term (1993-1996) hydrological changes in the Rhone river 总被引：1，自引：0，他引：1
The polychaete fauna of muddy bottoms off the Rhone delta (NW Mediterranean) was seasonally sampled at two sites at 70 m depth, from 1993 to 1996. During this period, five severe flood events occurred. A clustering analysis (distance coefficient of Whittaker) and three way fixed factor ANOVAs (site x season x year) showed strong year-to-year changes in species density and community structure, changes that masked seasonal variations. Total density increased by a factor of 3 and density of most species significantly increased following the first flooding event. Changes in the community structure were due to the successive dominance of a few species. The opportunistic species, such as Cossura sp., Mediomastus sp. and Polycirrus sp., exhibited peaks in density 1-3 months after the flood. These peaks were followed by a drastic decline. For species with a long life span, such as Sternaspis scutata, a slower but continuous increase in density was observed which was maintained for several months. The density fluctuations of these species exhibited a good correlation with river flow with time lags of 1-2 years. The successional dynamics observed are explained according to the geographical origin of the floods and the biology and feeding ecology of species. 相似文献
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The tolerance of the oligochaete Monopylephorus rubroniveus and the polychaete Streblospio benedicti to sediment-associated fluoranthene was characterized under normoxic (>80% dissolved oxygen saturation) and moderately hypoxic ( approximately 50% dissolved oxygen saturation) conditions. Under both conditions, M. rubroniveus was highly tolerant of fluoranthene. Streblospio benedicti was considerably less tolerant of fluoranthene compared with M. rubroniveus. In addition, S. benedicti was less tolerant to fluoranthene under moderately hypoxic conditions, although no differences in sensitivity between the two oxygen conditions were observed based upon median lethal tissue residues. Bioaccumulation factors were higher for S. benedicti exposed to moderate hypoxia, suggesting that behavioral adaptations to compensate for the lower dissolved oxygen increased its bioaccumulation of fluoranthene. The results of the present laboratory study demonstrate that (1). changes in annelid tolerance to fluoranthene under varying oxygen conditions is a species-dependent phenomenon and (2). the differential tolerance of these two annelids to these combined stressors is consistent with their relative abundances in the field. 相似文献
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台湾海峡西部海域软质海底多毛类的生态 总被引：2，自引：0，他引：2
本文根据１９８４－１９８５年４航次底栖生物调查资料，首次全面地研究了台湾海峡西部海域多毛类的种类组成，数量分布及其与环境因子的关系。结果表明，该海域多毛类４０４种，习见种１９１种，区系属亚热带性质；平均生物量４．３３ｇ／ｍ＾２，平均栖息密度６８个／ｍ＾２；有沿岸性和外洋性两种明显不同的生态类型，前者位于沿岸水系常年控制海域，种类多，数量较大，后者位于南部粗粒沉积物分布区，种类较少；多毛类高数量区与 相似文献
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厦门地区软相潮间带多毛类的生态 总被引：1，自引：0，他引：1
根据厦门地区１９９０年２月至１９９２年１月调查软相潮间带所获资料，研究了该区多毛类的种类组成，数量与分布，结果表明，该区多毛类种类丰富，共鉴定出１１８种，隶属于３７科８３属。其中，高潮区４０种，中潮区９０种，低潮区８３种。多毛类平均栖息密度８７个／ｍ＾３，平均生物量３．３３ｇ／ｍ＾２。 相似文献
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厦门港岩相潮间带多毛类的生态 总被引：2，自引：0，他引：2
本文根据１９８７年２、５、８、１１月调查资料，研究了厦门港岩相潮间带多毛类的种类组成、种类与数量的垂直分布、季节变化，并与大亚湾多毛类生态进行比较。结果表明，调查区域有多毛类４７种。平均栖息密度６０个／ｍ＾２，平均生物量１．７８ｇ／ｍ＾２，潮汐作用影响多毛类的种数、密度、生物量的垂直分布。多毛类数量的季节变化不甚明显，但冬季的栖息密度和春季的生物量较高。 相似文献
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《Marine Policy》2015
MPAs and stakeholder education are marine conservation cornerstones, but data to assess adherence to regulations and the success of educational methods are missing. Local MPAs have been established to protect inter-tidal mudflats and shore users from bait collection which is a contentious worldwide issue. Video cameras monitored activity and confirmed if collectors adhered to the rules at three UK sites with different MPA systems. An educational approach (a voluntary code leaflet) was also assessed through stakeholder discussion and observation. Fareham Creek and Dell Quay supported a considerable number of collectors with none observed at Pagham Harbour. At Fareham Creek bait dug areas were evident in discrete patches in unprotected and protected areas, but observed collectors mainly used the latter. The failure to exclude collectors is due to the lack of enforcement. At Dell Quay virtually all dug areas were outside protected areas and was confirmed by the camera footage. Success is attributed to regular on-the-ground ‘unofficial’ enforcement by the managing NGO. Of the retailers, 75% had heard of the code and the majority stated they followed it. However, none of the 26 collectors observed followed a key rule (e.g. backfilling holes). Local marine conservation is relatively cheap and can be effective, but only if: management matches the actual pressure; scientific evaluation for all components (including education) is integrated from the beginning; adequate site enforcement is included; education methods are active, two-way and sustained. 相似文献
7.
Chirananda De 《Marine Georesources & Geotechnology》2013,31(3):209-220
The marine polychaete Diopatra cuprea (Bosc) produces tubes that protrude above the sediment surface. To the part above the sediment surface the worm attaches foreign particles. A sharp boundary separates the parts above and below the sediment surface. With subsequent erosion, part of the tube without attached particles becomes exposed and this exposed part indicates the amount of erosion. With subsequent sedimentation, the tubes are enlarged upward and the sharp boundary is found below the sediment surface indicating the amount of subsequent sedimentation. This mode of construction of tubes during an average life span of two years renders tubes as simple but excellent natural tools for precise and easy measurement of the latest annual rates of erosion and deposition in coastal areas, data that are essential for the solving of coastal engineering and geoenvironmental problems. Comparison of this tool with expensive long-term coastal profiling data in four areas in the Bay of Bengal coast indicates its correctness and high applicational value. This revised model can be applied to modern coastal environments only for calculating latest annual rates of both erosion and deposition as correctly as latest physical techniques. Being based on the similar organosedimentary principle, it distinctively contrasts with the earlier model of Myers which provides information on the amount of sediment accumulation only without any time connotation and, it may generate erroneous results if applied to the geologic past unless some limitations evolved in the processes of dewatering, compaction, lithification and diagenesis are removed. 相似文献
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Benthic faunal data is regularly collected worldwide to assess the ecological quality of marine environments. Recently, there has been renewed interest in developing biological indices able to identify environmental status and potential anthropogenic impacts. In this paper we evaluate the performance of a general polychaete/amphipod ratio along the Norwegian continental shelf as an environmental indicator for offshore oil and gas impacts. Two main trends are apparent: first, a contamination gradient is discernible from where production takes place compared to stations 10,000 m away. Second, the quality of the marine environment has improved over time. These results are consistent with monitoring reports employing a combination of uni- and multi-variate statistics. Thus, we consider this ratio as a relatively simple, useful and potentially cost-effective complement to other more demanding assessment techniques. Because of its strong theoretical basis, it may also be useful for detecting ecological change as a result of other activities. 相似文献
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