南黄海西部地区浅层气的浅部埋藏地质背景   总被引：2，自引：1，他引：1  

顾兆峰  张志珣  刘怀山  蓝先洪 《海洋科学》2008,32(7):46-51

根据南黄海西部地区6000km多的浅地层剖面解释成果,对浅层气埋藏的载气地质体和地层时代两方面进行了分析。结果表明,南黄海西部地区浅层气主要存在于埋藏三角洲相、古湖泊相、古河道相、古潮沟相地质体中,在中更新世晚期以来的两期海相地层（全新世和晚更新世）和两期陆相地层（玉木冰期、里斯冰期）中都存在浅层气的地震反射。  相似文献   

长山群岛海区春季水温垂直结构分析   总被引：1，自引：0，他引：1  

李庆红  赵宏杰  张磊  蔡佳 《海洋技术学报》2008,27(1):101-105

利用海军大连舰艇学院2006年4月长山群岛海区的CTD调查资料,系统分析了该季节长山群岛海区的温度垂直结构,并探讨了其形成机理。分析指出:4月上、中旬是长山群岛海区季节性温跃层的生成期,群岛东侧和南侧边缘受黄海冷水团形成过程的影响,温跃层的出现概率和跃层强度都远远高于群岛内部;在生成时机上,群岛东侧和南侧边缘海域早于群岛内部水域。中间层和底层海水温度的垂直结构与海流有着很好的相关性,在海洋平流的作用下,海区会产生正跃层、逆跃层、冷中间层、暖中间层等复杂的温度垂直结构。上层海水温度结构主要受海面风场和气温的影响,较强的热辐射和充分的风力搅拌能够加速温跃层的生成。  相似文献   

杭州湾上海石化沿岸潮间带生态环境分析   总被引：1，自引：0，他引：1  

张进龙 《海洋湖沼通报》2008,(1):74-79

通过对1993～2002年杭州湾上海石化沿岸潮间带底栖动物群落结构的分析,得出上海石化处理达标后排放的工业废水对此段潮间带生态环境影响的范围和程度。自2002年到现在为止,本潮间带的底栖动物群落结构呈现一种适应性广、耐污染的结构组成.其生物多样性指数值在2.00～3.50之间。  相似文献   

浅层物探技术在近海灾害地质与工程地质调查中的应用     

王舒畋 《海洋地质译丛》2008,(1):6-12

随着海洋资源的开发与滨岸工程的建设,越来越多地遇到海洋地质灾害的影响与危害。为了避免并降低海洋地质灾害的影响程度,应开展海洋灾害地质与工程地质调查。二十多年来的实践经验表明,若采用以高分辨率地震为主,配合浅地层剖面、旁侧声纳、测深及磁力测量等综合浅层物探技术,对于了解海洋地质灾害因素与海底浅部工程地质特性等方面都能取得良好的效果,这是一种既经济又较快速地提供成果资料的好方法。  相似文献   

Genetic structure of Octopus vulgaris around the Iberian Peninsula and Canary Islands as indicated by microsatellite DNA variation   总被引：2，自引：0，他引：2  

Cabranes  C.; Fernandez-Rueda  P.; Martinez  J. L. 《ICES Journal of Marine Science》2008,65(1):12-16

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Positive feedback fishery: Population consequences of ‘crab-tiling’ on the green crab Carcinus maenas     

E.V. Sheehan  R.C. Thompson  R.A. Coleman  M.J. Attrill 《Journal of Sea Research》2008,60(4):303-309

Collection of marine invertebrates for use as fishing bait is a substantial activity in many parts of the world, often with unknown ecological consequences. As new fisheries develop, it is critical for environmental managers to have high quality ecological information regarding the potential impacts, in order to develop sound management strategies. Crab-tiling is a largely unregulated and un-researched fishery, which operates commercially in the south-west UK. The target species is the green crab Carcinus maenas. Those crabs which are pre-ecdysis and have a carapace width greater than 40 mm are collected to be sold to recreational anglers as bait. Collection involves laying artificial structures on intertidal sandflats and mudflats in estuaries. Crabs use these structures as refugia and are collected during low tide. However, the effect that this fishery has on populations of C. maenas is not known. The impact of crab-tiling on C. maenas population structure was determined by sampling crabs from tiled estuaries and non-tiled estuaries using baited drop-nets. A spatially and temporarily replicated, balanced design was used to compare crab abundance, sizes and sex ratios between estuaries. Typically, fisheries are associated with a reduction in the abundance of the target species. Crab-tiling, however, significantly increased C. maenas abundance. This was thought to be a result of the extra habitat in tiled estuaries, which probably provides protection from natural predators, such as birds and fish. Although crabs were more abundant in tiled estuaries than non-tiled estuaries, the overall percentage of reproductively active crabs in non-tiled estuaries was greater than in tiled estuaries. As with most exploited fisheries stocks, crabs in exploited (tiled) estuaries tended to be smaller, with a modal carapace width of 20–29 mm rather than 30–39 mm in non-tiled estuaries. The sex ratio of crabs however; was not significantly different between tiled and non-tiled estuaries. These results illustrate the potential to manage fished populations using habitat provision to mitigate the effects of fishing pressure.  相似文献   

Welcome mats? The role of seagrass meadow structure in controlling post-settlement survival in a keystone sea-urchin species     

Patricia Prado  Javier Romero  Teresa Alcoverro 《Estuarine, Coastal and Shelf Science》2009

Processes acting on the early-life histories of marine organisms can have important consequences for the structuring of benthic communities. In particular, the degree of coupling between larval supply and adult abundances can wield considerable influence on the strength of trophic interactions in the ecosystem. These processes have been relatively well described in rocky systems and soft-sediment communities, and it is clear that they are governed by very different bottlenecks. Seagrass meadows make interesting study systems because they bear structural affinities to both soft sediments as well as rocky substrates. We examined the early-life history of Paracentrotus lividus, one of the dominant herbivores in Mediterranean seagrass meadows, to identify the drivers of population dynamics in this species. We measured spatial and temporal variability in sea urchin post-settlement in 10 Posidonia oceanica meadows in the North-Western Mediterranean over a period of two years, and compared the numbers with the one-year old cohort a year later (i.e. the new population recruitment) as well as between successive size–age groups. Urchin post-settlers differed substantially between meadows but were present in both years in all meadows surveyed, suggesting that larval supply was not limiting for any of the studied sites. However, in six of the studied meadows, the one-year cohort of urchins was absent in both years, indicating that post-settlement processes strongly affected urchins in these meadows. In contrast, in four of the studied meadows, there was a strong coupling between post-settlers and one-year cohort individuals. These meadows were structurally different from the others in that they were characterised by an exposed matrix of rhizomes forming a dense seagrass mat. This mat apparently strongly mediates post-settlement mortality, and its presence or absence dictates the successful establishment of urchin populations in seagrass meadows. As the population aged, the relationship between size–age groups decreased evidencing the action of other processes. Yet, these results indicate that differences in physical structure are a vital bottleneck for sea urchin populations in seagrass meadows. Exploring the interaction between ecosystem structure and early-life history may provide a broader and more unified framework to understand the dynamics of a range of benthic habitats, including rocky substrates, soft sediments and seagrass meadows.  相似文献   

Model Test Study on Ice-Induced Vibrations of Compliant Multi-Cone Structures     

黄焱  史庆增  宋安 《中国海洋工程》2009,23(2):317-328

For the study on the ice-induced vibration of a compliant mono-cone structure,a series of model tests were performed from 2004 to 2006.In these tests,the ice sheet before the compliant conical structure was found to be failed in two-time breaking.Based on this important finding,model tests study of the ice force on a compliant multi-cone structure were performed from 2006 to 2007.in these tests,the ice sheet broke before each single cone non-simultaneously.The exciting energy of the total ice force was found to be in a wide range of frequencies,and the structure can be easily excited with nonlinear resonance.  相似文献   

Interactions between submarine channel systems and deformation in deepwater fold belts: Examples from the Levant Basin, Eastern Mediterranean sea   总被引：1，自引：0，他引：1  

Ian R. Clark  Joseph A. Cartwright 《Marine and Petroleum Geology》2009,26(8):1465-1482

Submarine channel levee systems form important hydrocarbon reservoirs in many deep marine settings and are often deposited within a structurally active setting. This study focuses on recent submarine channels that developed within a deepwater fold and thrust belt setting from the Levant Basin, eastern Mediterranean Sea. Compressional deformation within the study area is driven by the up-dip collapse of the Nile cone above the ductile Messinian Evaporites. Structures such as folds and strike slip faults exert a strong control on channel location and development over time. From this study four end-member submarine channel–structure interactions can be defined: Confinement, diversion, deflection and blocking. Each of these channel–structure interactions results in a distinct submarine channel morphology and pattern of development compared to unconfined channel levee systems. Each interaction can also be used to assess timing relationships between submarine channel development and deformation.  相似文献   

Distribution and spatial variation of hydrothermal faunal assemblages at Lucky Strike (Mid-Atlantic Ridge) revealed by high-resolution video image analysis     

Daphne Cuvelier  Joze Sarrazin  Ana Colao  Jon Copley  Daniel Desbruyres  Adrian G. Glover  Paul Tyler  Ricardo Serro Santos 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2026-2040

Whilst the fauna inhabiting hydrothermal vent structures in the Atlantic Ocean is reasonably well known, less is understood about the spatial distributions of the fauna in relation to abiotic and biotic factors. In this study, a major active hydrothermal edifice (Eiffel Tower, at 1690 m depth) on the Lucky Strike vent field (Mid-Atlantic Ridge (MAR)) was investigated. Video transects were carried out by ROV Victor 6000 and complete image coverage was acquired. Four distinct assemblages, ranging from dense larger-sized Bathymodiolus mussel beds to smaller-sized mussel clumps and alvinocaridid shrimps, and two types of substrata were defined based on high definition photographs and video imagery. To evaluate spatial variation, faunal distribution was mapped in three dimensions. A high degree of patchiness characterizes this 11 m high sulfide structure. The differences observed in assemblage and substratum distribution were related to habitat characteristics (fluid exits, depth and structure orientation). Gradients in community structure were observed, which coincided with an increasing distance from the fluid exits. A biological zonation model for the Eiffel Tower edifice was created in which faunal composition and distribution can be visually explained by the presence/absence of fluid exits.  相似文献