Responses of a Mediterranean soft bottom community to short-term (1993-1996) hydrological changes in the Rhone river

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.     

珠江三角洲及珠江口海区的空气微生物含量

１９９４年６，７月，调查了广州、深圳、珠海及珠江口海区的空气微生物粒子沉降量状况。发现空气微生物粒子总量、真菌粒子量、真菌粒子数／总菌粒子数百分比在三市中不一致。这三种数据一般是陆上的高于海上。随着距陆的增加，都市影响的减弱和海面的开阔，空气微生物含量呈减少之势，显示出海洋新鲜空气对陆上污染空气的调节、净化作用。文中还分析了空气微生物有关参数与气温、风力或相对湿度间的相关关系。     

黄海海域陆相中生界油气远景

黄海海域油气勘探已40余载，尚未实现油气突破，其找油前景引起石油地质学家的极大关注。根据前人的认识和最新研究成果，结合邻区油气地化资料，探讨了黄海海域中生界地层生、储、盖特征，特别是白垩系，它分布广，厚度大，烃源岩达到较好生油岩标准，并且生、储、盖组合理想，中生界是该区下部油气勘探首选目标。     

珠江三角洲地质灾害的模糊综合评价

珠江三角洲地质灾害种类的多样性与其所处的复杂地质环境和多变的气候条件密切相关。文章选用了地震活动、活动断裂、地壳升降运动、软土地基、地面塌陷以及冲、淤积等６个主要因素作为评价指标，并用模糊数学方法对珠江三角洲内１７个小区作了计算，结果表明该区大部分地区属于轻灾害区，只有滨海沿岸地区属于较重灾害区。     

山溪性可冲性强潮河口曹娥江高水位初步研究

应用多年的实测资料 ,分析了曹娥江河口高水位成因 ,结果表明 ,曹娥江河口洪水位具有山溪性和可冲性的特点 ,人类活动对高水位有较大影响。应用统计分析法和成因分析法推求 1 %设计高水位 ,讨论了成因分析法中上、下边界条件的选取 ,其选取原则对其他潮汐河口确定设计高水位具有借鉴意义     

基于二次散射的水污染遥感模型及其在珠江口水域的应用

根据水中悬浮物、污染物和水分子等的散射和吸收物理机制建模是实现水污染定量遥感的有效途径.基于一次散射的水污染遥感模型简单易行,但在浑浊度较大时其精度不高.在基于一次散射模型的基础上分析了多次散射的能量组成特点,提出再考虑二次散射可使模型的精度显著提高且不至于使模型过于复杂;导出了二次散射的补偿因子,同时给出了考虑二次散射因子的简单计算方法.将该模型应用于珠江口水域的水污染遥感的结果表明,较之基于一次散射的模型,考虑二次散射的水污染遥感模型在精度上有明显改进.遥感提取结果显示,珠江口水域重污染区主要分布在伶仃洋东北部,香港维多利亚港和深圳湾.     

珠江口盆地基底结构的综合地球物理研究

通过对珠江口盆地重磁资料的分析处理及反演计算，依据盆地的地质、地球物理特征，采取了针对性的综合地球物理研究思路与方法，对地震资料难以解决的珠江口盆地基底结构进行了研究，确定了盆地的重力和磁性基底深度，并对盆地内的断裂和基底岩性作了推断，提供了新的认识，为今后研究提供了依据。     

浙江南部海域富营养化和赤潮的探讨

本文探讨了浙江南部海域1990年春季发生赤潮期间的水化学特征和富营养化状况,及与赤潮生物的线性回归关系。分析结果表明,该海域出现高营养盐以至形成富营养化乃是江浙沿岸流和瓯江等河流径流及远岸区盐度锋辐聚的综合影响的结果。根据回归分析,NO_3-N,SiO_3-Si与浮游植物细胞密度之间存在着较为显著的负相关。亦即N,Si和高N/P比(35:1左右)可能是导致浮游植物(夜光藻)异常增殖的重要因素。     

渤、黄、东海内潮的数值模拟

在全球的海洋中,中国东海和临近海域是最显著的内潮生成地之一。本文采用NODC(Levitus) World Ocean Atlas 1998提供的季平均温、盐资料,计算海水的密度,并计算垂向密度梯度的最大值点,得到一个较符合海水实际的密度分层。使用三维非线性数值模型(将海洋分为2层)研究了潮汐(M2,S2,K1,O1分潮)作用下渤黄东海的内潮,揭示了整个海区内潮起伏的空间分布,结果发现大振幅的波动均发生在台湾东北(冲绳海槽)海域和中国近海地形突变之处,其中前者更显著。对于各分潮模拟得到的表面潮与TOPEX/Poseidon高度计资料基本一致。研究结果表明上层海水的深度和厚度的梯度对内潮有一定的影响;冬季分布区域比夏季小,强度比夏季大。     

Bulk particulate organic carbon in the East China Sea: Tidal influence and bottom transport

Five oceanographic surveys were carried out in the East China Sea (ECS) and Yellow Sea from 1999 to 2003. In all, seven different sections were surveyed, but one section (the PN section) was observed on every cruise. Two time-series stations were also surveyed, one located at the Changjiang River mouth, the other over the continental shelf in the PN section.We identified biogeochemical characteristics for waters close to the Changjiang Estuary and in the Kuroshio waters (KW), respectively. Resuspension is a strong feature near bottom over the ECS continental shelf, with suspended matter values 13 times higher than that for the surface. A model of particulate organic carbon (POC) dynamics based on a rectangle equation reveals that POC concentration close to the Changjiang Estuary varies with a semidiurnal period of ∼13 h, coinciding with the tidal period. The upper limit for POC residence times in the seasons we covered over the shelf are estimated to be on the order of weeks and generally increase seaward from near the Changjiang Estuary to the KW. Short POC residence times suggest that POC in the ECS is rapidly exported from euphotic waters.A nepheloid layer, observed as elevated suspended matter in near the bottom of the water column, is important in particle transfer over the shelf, especially in winter when the residual current flows mainly eastward. Cross-shelf transport of POC via the nepheloid layer is estimated to be 0.22 × 10¹² g yr⁻¹. Comparison with other work indicates that POC transport is ∼2% of the Changjiang POC input.