Nereis diversicolor: an Unreliable Biomonitor of Metal Contamination in the 'Ría de Bilbao' (Spain)     

J. I. Saiz-Salinas  G. Francés-Zubillaga   《Marine Ecology》1997,18(2):113-125

Abstract. Samples of the polychaete Nereis diversicolor O.F. M üller and surficial sediments from a clean and a polluted estuary were taken during a year at monthly intervals to determine, by comparison, the range of temporal fluctuations in trace metal concentrations. Whereas metal variations in surficial sediments were more pronounced in the polluted estuary, concentrations in N. diversicolor in both estuaries showed a wide range of temporal variation that surpassed that of surficial sediments. A clear decline in all metals studied (except Mn) from polluted sediments was noted after episodes of strong rainfall. In the reference estuary the fluctuations were less pronounced. Metal body burdens in N. diversicolor from the two estuaries were usually quite similar even though total levels in sediments differed considerably, indicating a lack of worm-sediment relationship. The low level of Cu, Cr and Pb in the tissues of N. diversicolor suggest a mechanism which prevents the polychaete from being exposed to these metals in highly polluted sediments. Therefore, it is concluded that N. diversicolor cannot be considered to be an ideal biomonitor of metal contamination in the polluted Bilbao Estuary.  相似文献   

夏季珠江口沉积物中营养盐剖面分布和界面交换通量   总被引：21，自引：4，他引：21  

潘建明  周怀阳  扈传昱  刘小涯  董礼先  张美 《海洋学报》2002,24(3):52-59

通过对夏季珠江口区域沉积物间隙水营养盐剖面分析,调查了营养盐含量分布和特征,探讨了有机物的降解特性、营养盐的底部通量估算和作用.结果表明,珠江口沉积物间隙水中营养盐以高含量铵盐为主要的存在形式,沉积物中有机物的降解反应主要在厌氧状态下进行,底部水体铵盐的增加来源于底部沉积物有机质的降解释放,而且对水体的营养盐循环有较大的贡献.  相似文献   

厄尔尼诺现象和浙江近海鲐鲹鱼渔获量变化关系──长江口ENSO渔场学问题之二   总被引：12，自引：0，他引：12  

洪华生  何发祥  杨圣云 《海洋湖沼通报》1997,(4)

本文研究浙江近海1970年到1992年鲐鱼渔获量变化与Elnino现象的关系，结合捕捞强度，长江中下游汛期（4—9月）降水量距平年际变化综合分析，探讨浙江近海鲐鱼渔获量变动规律，为合理开发渔业资源提供科学依据。  相似文献   

九龙江河口区磷的转移和入海通量   总被引：1，自引：3，他引：1  

陈松  廖文卓  骆炳坤  许爱玉 《台湾海峡》1996,15(2):137-142

1992～1993年4个航次的调查研究结果表明，九龙江河口区总磷的分布和转移受悬浮物含量明显控制。当SPM含量低时，其迁移过程接近理想行为；SPM含量高时则为非理想行为。估算得出，九龙江水体总磷的平均人海通量为1．47×103t／a。其中，溶解态磷为0．43×103t／a，约占29％；颗粒态磷占71％，九龙江水磷的输入以颗粒态为主。溶解态磷的分布，基本上在某一水平上了波动，其入海通量受环境影响很小，可能意味着颗粒磷的缓冲作用。  相似文献   

Sediment Deposition and Resuspension in Mouth Bar Area of the Yangtze Estuary   总被引：1，自引：0，他引：1  

L I Jinfa 《中国海洋工程》2000,14(3):339-348

—A comprehensive analysis is conducted based on observations on topography.tidal current.salinity.suspended sediment and bed load during the years of 1982.1983.1988.1989.1996 and 1997 in theYangtze Estuary.Results show that the deformation of tidal waves is distinct and the sand carrying capaci-ty is large within the mouth bar due to strong tidal currents and large volume of incoming water and sedi-ments.Owing to both temporal and spatial variation of tidal current.deposition and erosion are extremelyactive.In general a change of up to 0.1 m of bottom sediments takes place during a tidal period.The maxi-mum siltation and erosion are around 0.2 m in a spring to neap tides cycle.The riverbed is silted duringflood when there is heavy sediment load.eroded during dry season when sediment load is low.The annualaverage depth of crosion and siltation on the riverbed is around 0.6 m.In particular cases.it may increaseto 1.4 m to 2.4 m at some locations.  相似文献   

Characterization of chromophoric dissolved organic matter (CDOM) in the Baltic Sea by excitation emission matrix fluorescence spectroscopy   总被引：11，自引：0，他引：11  

Piotr Kowalczuk  Joanna Sto&#x;-Egiert  William J. Cooper  Robert F. Whitehead  Michael J. Durako 《Marine Chemistry》2005,96(3-4):273-292

Chromophoric dissolved organic matter (CDOM) is the major light absorber in the Baltic Sea. In this study, excitation emission matrix (EEM) fluorescence spectra and UV–visible absorption spectra of CDOM are reported as a function of salinity. Samples from different locations and over different seasons were collected during four cruises in 2002 and 2003 in the Baltic Sea in both Pomeranian Bay and the Gulf of Gdansk. Absorption by CDOM decreased with increased distance from the riverine source and reached a relatively stable absorption background in the open sea. Regression analysis showed that fluorescence intensity was linearly related to absorption by CDOM at 375 nm and a_CDOM(375) absorption coefficients were inversely related to salinity. Analysis of CDOM-EEM spectra indicated that a change in composition of CDOM occurred along the salinity gradient in the Baltic Sea. Analysis of percent contribution of respective fluorophore groups to the total intensity of EEM spectra indicated that the fluorescence peaks associated with terrestrial humic components of the CDOM and total integrated fluorescence decreased with decreasing CDOM absorption. In contrast, the protein-like fraction of CDOM decreased to a lesser degree than the others. Analysis of the percent contribution of fluorescence peak intensities to the total fluorescence along the salinity gradient showed that the contribution of protein-like fluorophores increased from 2.6% to 5.1% in the high-salinity region of the transect. Fluorescence and absorption changes observed in the Baltic Sea were similar to those observed in similar transects that have been sampled elsewhere, e.g. in European estuaries, Gulf of Mexico, Mid-Atlantic Bight and the Cape Fear River plume in the South Atlantic Bight, although the changes in the Baltic Sea occurred over a much smaller salinity gradient.  相似文献   

长江口深水航道治理一期工程实施对北槽拦门沙的影响   总被引：8，自引：3，他引：8  

刘杰乐嘉海  胡志峰丁光明 《海洋工程》2003,21(2):58-64

介绍了长江口拦门沙发育及其特点和北槽航道拦门沙形成机理，利用长江口深水航道治理一期工程实施后的地形资料分析治理工程对北槽航道拦门沙影响。结果表明：治理工程建成后，增加了主槽流速，减少了航道回淤，打通北槽航道拦门沙，增加了航道水深，治理工程效果明显。  相似文献   

长江口三维潮流数值计算及动力分析   总被引：10，自引：1，他引：10  

于凤香  宋志尧  李瑞杰 《海洋湖沼通报》2003,(3):14-23

采用三维动力学数学模型对长江口潮流场进行了计算，对长江口潮流流态在一个潮周期内逐时进行了分析，并对长江口南支盐水倒灌从动力学角度进行了初步探讨。计算结果表明：文中模型较好地重演长江口潮流场，可以用于大型复杂河口工程实际中的潮流场的计算和分析。  相似文献   

珠江口水体的三氮特征     

丘耀文 《热带海洋学报》1992,(3)

本文据珠江口周年(1987年2月至1988年2月)调查资料,分析了珠江口桂山岛附近海域的三氮变化规律,讨论了三氮之间的相互关系,通量和停留时间以及各种因素对三氮的影响。结果表明:珠江河口水中三氮的时空分布具有夏、冬季含量高,春、秋季含量低,并随向外海方向递减的特点;三氮之间的关系可分别用倒指数方程Y=exp(A+B/X)的数学模式描述;NH_4-N,NO_3-N,NO_2-N的通量和停留时间分别为33.9,401.0,15.8g·atN/s和3.84,3.96,4.41d。  相似文献   

基于BP人工神经网络的水体遥感测深方法研究   总被引：5，自引：0，他引：5  

王艳姣  张鹰 《海洋工程》2005,23(4):33-38

利用Landsat7ETM＋遥感图像反射率和实测水深值之间的相关性,建立了动量BP人工神经网络水深反演模型,并对长江口南港河段水深进行了反演.结果表明：具有较强非线性映射能力的动量BP神经网络模型能较好地反演出长江口南港河段的水深分布情况;由于受长江口水体高含沙量的影响,模型对小于5 m的水深值反演精度较高,而对大于10 m的水深值反演精度较低.  相似文献