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1.
长江口浮游动物生态分布特征及其与环境的关系 总被引：32，自引：0，他引：32
采用2002年8月监测资料,对长江口海域的浮游动物生态分布特征(种类组成、群落结构及多样性等)分四个区域进行了分析,并探讨了浮游动物个体数、生物量分布与环境因子的关系。结果表明,调查海域共鉴定出浮游动物74种,桡足类28种,水母类7种,毛颚类6种,另外还鉴定出多种浮游虾类和浮游幼体。长江口外海区浮游动物种类最多,为55种,长江口混合区其次,为42种,长江口南支和南汇嘴附近海域种类较少,分别为11种和13种。长江口南支和南汇嘴附近海域优势种类为火腿许水蚤(Schmackeria poplesia)和虫肢歪水蚤(Tortanus vermiculus),长江口混合区为背针胸刺水蚤(Centropages dorsispinatus)、真刺唇角水蚤(Labidocera euchaeta),而中华哲水蚤(Calanus sinicus)和肥胖箭虫(Sagitta enflata)为长江口外海区的优势种类。浮游动物个体数大小为:长江口南支<长江口混合区<长江口外海区<南汇嘴;而生物量高低依次为:长江口外海区>长江口混合区>南汇嘴>长江口南支。长江口外浮游动物种类丰富,多样性指数较高,均匀度较好。经相关分析结果表明,浮游动物个体数与生物量存在明显的正相关,个体数与Hg呈正相关,与化学需氧量呈负相关;生物量与盐度、酸碱度、叶绿素a呈正相关,与溶解氧、化学需氧量、活性磷酸盐、无机氮表现为负相关。 相似文献
2.
三峡工程一期蓄水后长江口及其邻近水域浮游动物的群落结构 总被引：6，自引：0，他引：6
长江三峡工程自2003年6月1日~10日进行一期蓄水。为研究长江三峡工程蓄水对长江口环境的影响,在一期蓄水后组织了长江口及其邻近海域环境的综合调查。根据采集的大中型和中小型浮游生物样品的分析数据,结合环境参数,对长江河口及邻近海域浮游动物种类组成及群落结构进行了多元分析,研究浮游动物群落结构及其影响因子。浮游动物种类数为289个(含31种浮游幼虫)。据各站位浮游动物种类组成和丰度,用聚类分析法可将该水域的浮游动物分为4个群落。整个调查海区,中华哲水蚤最占优势。相关性分析表明,夏季影响浮游动物群落结构的主要环境因子为盐度。 相似文献
3.
根据2007年到2008年5月和8月长江口水域共4个航次的监测资料,对长江口水域浮游动物的生物量、优势种、种类数和多样性指数的平面分布及其与环境的关系进行了分析。结果表明,调查水域浮游动物生物量值8月份大于5月份生物量,分布格局呈近岸向外海递增趋势。5月出现的优势种虫肢歪水蚤(Tortanus vermiculus)和真刺唇角水蚤(Labidoceraeuchaeta)分布于河口水域以及咸淡交错水域。8月的背针胸刺水蚤(Centropages dorsispinatus)和太平洋纺锤水蚤(Acartiapacifica)分布于河口水域和咸淡交错水域,肥胖箭虫多分布于口外近海水域。中华哲水蚤(Calanus sinicus)在4次采样均出现,是口外近海水域的主要优势种。调查水域浮游动物种类数和多样性指数分布格局呈近岸向外海递增趋势。盐度、温度及主要优势种中华哲水蚤是影响长江口浮游动物分布的重要因子。 相似文献
4.
本文以2021年5月长江口南北支采集的表层水为研究对象,通过测定氢、氧同位素,溶解有机碳(DOC)浓度,有色溶解有机质(CDOM)的吸收光谱和荧光光谱参数,探讨了夏季长江口北支、南支(北港、北槽、南槽)水体溶解有机质的组成、分布及其影响因素。沿长江下游到河口近海,南、北支DOC浓度分别为1.68±0.16mg/L和1.46±0.31mg/L,CDOM的吸光系数a350分别为2.37±0.61m-1和1.59±0.24m-1。南支整体具有“高类腐殖质、低类蛋白”的特征,北支则具有“低类腐殖质、低类蛋白”的特征,这可能与南北支的径流量差异有关。在南北支不同分汊河道(北支、南支北港、南支北槽和南支南槽)中,南槽和北支有类似的海水入侵特征,但南槽具有较强的类蛋白组分输入,而南支北港和北槽样品间无显著差异,均表现为河流有机质为主的特征。对比2011年长江南北支DOC和CDOM数据显示,作为长江主河道的南支在2021年无明显变化,而北支有显著的变化。这些结果综合表明长江口DOM的变化格局可能受水动力条件(径流量)、人类活动因素共同作用的影响。比较全球河口DOC和CDOM浓度数据后发现,不同区域的河口具有明显的差异,这可能是因为不同流域在植被覆盖、工农业生产水平、水利工程强度、以及气候变化对土壤侵蚀作用等方面的差异。 相似文献
5.
根据2016年7月和2017年1月在黄海进行的57个站位的调查数据,研究了大型网采集的浮游动物的种类组成、丰度、生物量、群落聚类、优势种、多样性、均匀度、丰富度以及与环境因子的关系。本次调查共鉴定出浮游动物97种,其中夏季67种,冬季76种。该海区夏季浮游动物的丰度和生物量的高值区分布在黄海冷水团和长江口附近海域,冬季分布在黄海暖流主轴部分。根据各站位的地理位置和浮游动物相似程度,对黄海浮游动物Cluster聚类和MDS多维定标分析,将夏季划分为4个群落,将冬季划分为3个群落。共计有8个优势种类,夏季的优势种多为桡足类,冬季除中华哲水蚤(Calanus sinicus)优势度占绝对优势外,其余优势种的优势度较为相近。将浮游动物的丰度、生物量和生物多样性指数和环境因子做相关性分析得出:温度、盐度是影响黄海浮游动物群落结构的主要影响因子。 相似文献
6.
长江口及邻近海区浮游动物总生物量分析 总被引：3，自引：1，他引：3
依据1998年11月、1999年5月、2000年11月和2001年5月4个航次在长江口及其邻近海区调查所获得的大型浮游生物网垂直拖样品，对测区的浮游动物总生物量的总体水平，分布和种类组成进行了分析，并将研究结果与1958—1959年全国海洋普查的资料和1985—1986年“三峡工程对长江口及邻近海区生态与环境的影响”调查资料进行了同测区、同月份的对比。结果显示，测区1999年和2001年5月份浮游动物总生物量近几年比50年代末和80年代中期有明显增加，分别增加了1．43—1．76和0.95—1.22倍；11月份总生物量的分布格局和种类组成没有大的变化。这可能反映长江口及其邻近海区浮游动物的变动趋势，但仍需要更多的资料证实。 相似文献
7.
河口营养物基准是河口营养状态参数对生态环境不产生不良或有害影响的最大阈值。本文首先基于2015—2018年长江口环境现场调查数据开展河口内部分区,再通过主成分分析、相关性分析和线性回归分析等方法,筛选长江口营养物基准关键指标,之后采用频数分布法和压力-响应模型法得出基准推荐值,最后将赤潮优势藻培养实验得到的生态响应值作为参考。结果表明:根据盐度分布与地形特征,长江口可分为口门区和口外区两个生态区。可溶性无机氮(dissolved inorganic nitrogen,DIN)和可溶性活性磷酸盐(soluble reactive phosphorus,SRP)是制定长江口营养物基准的关键指标。口门区DIN和SRP的基准推荐值分别为0.614和0.029mg/L,口外区基准推荐值分别为0.295和0.008 mg/L。该结果有望为长江口富营养化评估和营养物标准制定等环境管理工作提供科学依据。 相似文献
8.
长江口及毗邻海域粪大肠菌和细菌总数在夏秋季的变化 总被引：1，自引：0，他引：1
2005年夏、秋季对长江口及毗邻海域(长江口、杭州湾和舟山海域)进行了粪大肠菌群和细菌总数的调查研究,并分析了近10年来的变化趋势,结果表明:夏季长江口及毗邻海域表层水体分大肠菌数平均值20个/L,仅长江口的西部海域粪大肠菌群数量在40~80个/L之间,其余海域基本未检出;秋季表层水体粪大肠菌群数量平均为101个/L,变幅范围为20~24000个/L,其中横沙一带海域存在1个数量为105个/L以上的高值区;夏季长江口及毗邻海域表层水体细菌总数平均为6.4×102cfu/mL,变幅范围为2.0×102~7.3×103cfu/mL,高值区位于舟山群岛以东海域、长江口的中北部及南部等海域,细菌总数在103cfu/mL以上;秋季表层水体细菌总数平均为4.7×103cfu/mL,明显高于夏季,变幅范围为1.3×103~1.8×104cfu/mL,高值区主要出现在长江口东南部、杭州湾西部、舟山海区的中北部等海域,细菌总数在104~105cfu/mL之间;1996—2005年期间,全海域及各海区粪大肠菌群数量在1999年均达到最高,然后逐渐下降,在1996—1999年间海域的细菌数量呈明显的上升趋势,2000年以后数量逐渐减少,估计与海域的有机污染程度下降有关。 相似文献
9.
在水质监测及水环境调查中,盐度分析工作是一个重要环节,根据现行的<水质分析国家标准>,<海洋调查规范>,地表水及生活用水的盐度分析一般采用前者,而海洋水样则采用后者.对于长江口及其近海水域既有适用<水质分析国家标准>(TB11896-89)的区段,又有适用<海洋调查规范>的区域,亦有两者都不适用的部分.本文通过对长江口盐度分析方法的研究.阐述了该区域进行水样盐度分析的各种方法的适用范围及提高效率保证成果质量的办法.最后作者提出的人海河流河口及其近海水域盐度分析的方法是:按取样地点位于河口的具体位置来选择其分析方法. 相似文献
10.
长江口及邻近海域枯季水质生态模拟研究 总被引：2，自引：0，他引：2
将一个由水动力、粘性泥沙和水质生态模型搭建的综合模拟系统应用于长江口及邻近海域,采用枯季(11—4月)平均水文气象条件设置并驱动模型。将模拟结果与2003年3月观测资料及其他历史资料进行比对发现,模拟结果总体上很好地再现了研究海区枯季温度、盐度、悬浮泥沙、无机氮、无机磷等生态水质要素的水平和垂直分布趋势,说明模型可反映研究海区的水动力、泥沙和水质生态的关键过程。模拟结果中,DIN的分布趋势呈现出"近岸河口高、外海低"的特点,长江口和钱塘江口附近含量最高;DIP的高浓度区不仅仅在长江口及杭州湾,在浙江近海其它区域的浓度值也较高;浮游植物量最大的区域位于舟山以东海域。另外,3个条件响应数值试验表明,枯季长江口及邻近海区无机氮和无机磷均处于富余状态,尤其是无机氮,即使在陆源输入减半的情况下,仍然富余,没有被浮游植物充分利用;研究区域的高质量浓度悬浮泥沙通过限制光照强度控制着浮游植物的生长。 相似文献
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
14.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
15.
16.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
17.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
19.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
20.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献