排序方式: 共有74条查询结果,搜索用时 15 毫秒
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Beaumont NJ Austen MC Atkins JP Burdon D Degraer S Dentinho TP Derous S Holm P Horton T van Ierland E Marboe AH Starkey DJ Townsend M Zarzycki T 《Marine pollution bulletin》2007,54(3):253-265
This paper identifies and defines ecosystem goods and services provided by marine biodiversity. Case studies have been used to provide an insight into the practical issues associated with the assessment of marine ecosystem goods and services at specific locations. The aim of this research was to validate the definitions of goods and services, and to identify knowledge gaps and likely difficulties of quantifying the goods and services. A validated theoretical framework for the assessment of goods and services is detailed, and examples of the goods and services at a variety of case study areas are documented. These results will enable future assessments of marine ecosystem goods and services. It is concluded that the utilisation of this goods and services approach has the capacity to play a fundamental role in the Ecosystem Approach, by enabling the pressures and demands of society, the economy and the environment to be integrated into environmental management. 相似文献
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Silicified flake conglomerates and in situ stratiform stromatolites of the Upper Proterozoic (c. 700-800 Ma) Limestone-Dolomite 'Series', central East Greenland, contain well preserved microfossils. Five stratigraphic horizons within the 1200 m succession contain microbial mat assemblages, providing a broad palaeontological representation of late Proterozoic peritidal mat communities. Comparison of assemblages demonstrates that the taxonomy and diversity of mat builder, dweller, and allochthonous populations all vary considerably within and among horizons. The primary mat builder in most assemblages is Siphonophycus inornatum, a sheath-forming prokaryote of probable but not unequivocally established cyanobacterial affinities. An unusual low diversity unit in Bed 17 is dominated by a different builder, Tenuofilum septatum, while a thin cryptalgal horizon in Bed 18 is built almost exclusively by Siphonophycus kestron. Although variable taphonomic histories contribute to observed assemblage variation, most differences within and among horizons appear to reflect the differential success or failure of individual microbial populations in colonizing different tidal flat microenvironments. Twenty-two taxa are recognized, of which two are described as new: Myxococcoides stragulescens n.sp. and Scissilisphaera gradata n. sp. 相似文献
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GPS水准拟合模型的优选 总被引:13,自引:1,他引:13
根据拟合模型的优选标准,提出在GPS水准的高程异常拟合中如何找出最优拟合函数的实施途径。并给出相应的统计检验方法。 相似文献
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Dye AH 《Marine environmental research》2006,62(5):341-355
Disturbance is an important factor in structuring ecological communities, exerting its influence through changes to the physical environment and to the trajectories of successional processes. Marine environments are subject to a wide range of disturbances and while much is known about the effects of disturbance on macrobenthos in unconsolidated sediments, little is known about the responses of meiobenthos to disturbance in consolidated sediments, such as mangroves. Trampling was used to study the response of meiobenthos to disturbance in mangrove sediments. Even light trampling appeared to break up the mangrove root mat and increased the proportion of fine sediment. Densities of meiobenthos increased 2-3-fold in disturbed sediments, but there was no evidence of disproportionate abundance. Temporal variability was similar in all treatments, but spatial variability increased 4-5-fold in disturbed sediments. Effects persisted for at least 24 months, with little evidence of convergence of treatments. Meiobenthos may have exploited the increase in habitat resulting from loss of the root mat and possibly benefited from increased food from the decomposition of root material. These effects are likely to persist for several years because of the minimal recovery of the root mat. 相似文献
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