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41.
渤海南部海底沉积物颜色的研究   总被引:1,自引:0,他引:1  
  相似文献   
42.
Abstract.  The major problem in coastal areas of developing countries is disturbance caused by anthropogenic influence. This disturbance can be quantified by analysing the distribution and composition of marine communities using uni- and multivariate techniques and the biotic index. A study of benthic macrofauna was carried out along the São Sebastião Channel, northern coast of São Paulo State, Brazil, in an area with a submarine outfall, a petroleum terminal and a commercial harbour. Sampling was undertaken seasonally, by means of a van Veen grab (0.1 m2) at 15 oceanographic stations, from November 1993 to August 1994. A total of 392 species were identified (129 Polychaeta, 127 Mollusca, 98 Crustacea, 28 Echinodermata and 10 other phyla). The sedimentary pattern recorded for the São Sebastião Channel is very heterogeneous, influenced mainly by strong wind-driven currents, and differs from nearby shelf areas. The study area could be divided into three regions based on sediment texture and fauna: one region dominated by medium and coarse sand with low values of organic carbon; a second area where pelitic fractions were dominant with high values of organic carbon and nitrogen; and a third region characterised by fine and very fine sand, presenting intermediate organic carbon values. No temporal significant variation in abundance and species composition was found, except in autumn. The use of the 'marine Biotic Coefficient' showed the same ecological trend as the faunal abundance and demonstrated that the central continental region of the channel is affected by human activities.  相似文献   
43.
Abstract-Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shen-zhen Bay and are important "refueling" point along the East Asian/Australian flyway of migratory birds.The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid eco-nomic developments in Hong Kong and Shenzhen in recent decades. Microinfauna of Mai Po and Futianmudflats was investigated in December 2000 and the faunal data were used to assess their environmentalquality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Kengintertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfaunaand used as reference mudflats. Shannon-Weaver species diversity index (I_(sd)), biotic coefficient (C_b)and macrofaunal pollution index (I_(mp)) of the macrofauna community on four intertidal mudflats wereused to  相似文献   
44.
Al, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti and Zn concentrations have been determined in surface sediment samples collected in the Taranto Gulf (Ionian Sea, Southern Italy) in order to evaluate their levels and spatial distribution in this important area of the Mediterranean Sea. For various metals, the geoaccumulation index has been calculated as a criterion to assess if their concentrations represent contamination levels or can be considered as background levels. The results show that metals concentrations in sediments can be considered near the background levels found in the Mediterranean Sea.Analytical results have been elaborated by using a Geographical Information System (GIS) software to show metals accumulation areas. Using multivariate statistical analysis, we evaluate the possibility to distinguish the sampling stations, in relation to their geographical position. Results have showed metals distribution in the Taranto Gulf is principally influenced by industrial and urban wastes, located mostly in the northern coastal area of the Ionian Sea. Rivers in the Basilicata region and prevailing anticlockwise marine currents are further factors influencing metal accumulation in sediments.  相似文献   
45.
南海海域叶绿素浓度分布特征的卫星遥感分析   总被引:17,自引:5,他引:17  
陈楚群  施平  毛庆文 《热带海洋学报》2001,20(2):66-70,T001
介绍了第二代海洋水色传感器SeaWiFS资料的特点汲其基本处理方法,海水叶绿素浓度提取方法,对南海域表层海水叶绿素浓度分布的时空变化特征及其与营养物质和南海环流的关系进行了初步分析。  相似文献   
46.
Within the European DIADEM project, a data assimilation system for coupled ocean circulation and marine ecosystem models has been implemented for the North Atlantic and the Nordic Seas. One objective of this project is to demonstrate the relevance of sophisticated methods to assimilate satellite data such as altimetry, surface temperature and ocean color, into realistic ocean models. In this paper, the singular evolutive extended Kalman (SEEK) filter, which is an advanced assimilation scheme where three-dimensional, multivariate error statistics are taken into account, is used to assimilate ocean color data into the biological component of the coupled system. The marine ecosystem model, derived from the FDM model [J. Mar. Res. 48 (1990) 591], includes 11 nitrogen and carbon compartments and describes the synthesis of organic matter in the euphotic zone, its consumption by animals of upper trophic levels, and the recycling of detritic material in the deep ocean. The circulation model coupled to the ecosystem is the Miami isopycnic coordinate ocean model (MICOM), which covers the Atlantic and the Arctic Oceans with an enhanced resolution in the North Atlantic basin. The model is forced with realistic ECMWF ocean/atmosphere fluxes, which permits to resolve the seasonal variability of the circulation and mixed layer properties. In the twin assimimation experiments reported here, the predictions of the coupled model are corrected every 10 days using pseudo-measurements of surface phytoplankton as a substitute to chlorophyll concentrations measured from space. The diagnostics of these experiments indicate that the assimilation is feasible with a reduced-order Kalman filter of small rank (of order 10) as long as a sufficiently good identification of the error structure is available. In addition, the control of non-observed quantities such as zooplankton and nitrate concentrations is made possible, owing to the multivariate nature of the analysis scheme. However, a too severe truncation of the error sub-space downgrades the propagation of surface information below the mixed layer. The reduction of the actual state vector to the surface layers is therefore investigated to improve the estimation process in the perspective of sea-viewing wide field-of-view sensor (SeaWiFS) data assimilation experiments.  相似文献   
47.
边坡整体稳定的可靠性分析方法   总被引:8,自引:0,他引:8  
边坡整体滑动稳定性的可靠性分析是建立在土体具有的抗力大于荷载效应的概率基础上进行设计和校验的。在条分法的基础上推导出了进行边坡稳定可靠性分析的统一极限状态方程 ,将土的容重γ、内摩擦角φ、粘聚力 c作为随机变量 ,当其为非正态分布时 ,进行当量正态化 ,考虑变量相关的情况 ,用简化相关法对随机变量进行统计分析 ,并以 Bishop圆弧滑动法为例 ,用 JC法求解边坡的可靠性指标及失效概率 ,给出计算安全系数和可靠性指标的算法程序。并就影响可靠性指标的因素如抗剪强度指标、变量分布形式、土性参数的变异性等进行了讨论。  相似文献   
48.
用国家海洋局1975—1982年间在黄东海调查的海水透明度数据换算为悬浮体含量,用NOAA卫星高分辨率辐射计数据计算悬浮体含量,以绘制悬浮体含量分布图。分布图显示,研究区有三个悬浮体含量高值区,位于苏北浅滩、长江口、成山角沿岸水域。研究表明,风浪是影响悬浮体含量的海洋外部的主要因素。层化参量是影响悬浮体含量海洋内部的主要因素。  相似文献   
49.
盐度对双棘黄姑鱼仔鱼活力及仔稚鱼生长的影响   总被引:8,自引:0,他引:8  
分别用不同盐度梯度海水对双棘黄姑鱼仔鱼进行饲养试验。结果表明:盐度为17.0.22.0、27.0.31.0~33.0的4个试验组仔鱼的不投饵存活系数分别为5.38、7.35、6.46、6.18;各盐度组仔稚鱼的生长速度没有显著差异(P〉0.05),各组仔鱼经25d的培养,其平均全长为18.8~19.2mm;盐度22.0及27.0的海水中仔稚鱼呈较高的存活率,各盐度组的平均存活率为36、0%、48.5%、46.7%和39.2%.  相似文献   
50.
琼州海峡岸礁潮间带生物   总被引:14,自引:0,他引:14  
本文记录了2000年7月琼州海峡西口雷州半岛灯楼角珊瑚岸礁调查采集的25种造礁石珊瑚,以及栖息于湖间带的7类39科88种底栖生物,其大多数种类属于印度-西太平洋热带区系。优势类群是软体动物和节肢动物。珊瑚礁段底栖生物的平均生物量、栖息密度和多样性值分别为1173.30g/m^2,790.0个/m^2和5.69,由于造礁石珊瑚的存在为其他底栖生物提供了良好的生态环境,从而丰富了本区底栖生物的种类组成、数量、分布和群落结构。  相似文献   
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