渤海海峡冬季表层海水中溶解无机碳分布特征分析

根据2010 年2 月—2010 年3 月的调查数据, 探讨了冬季渤海海峡及其附近表层海水中溶解无机碳体系的分布特征。结果表明: 表层水体中TA、DIC 和HCO₃^- 的浓度分布总体上呈现出海峡西南部高东北部低的分布趋势。西南部出现的高值区, 与该区域靠近莱州湾, 受莱州湾水体污染影响有关。调查海域TA 与表层水的温度相关性明显, pH 与叶绿素的相关性较高。水温和Chl-a 浓度是影响水体中无机碳体系分布变化的重要因素。其中, 水温对HCO₃^- 的影响要明显强于DIC。海峡南北两侧水体交换的差异, 是导致海峡南部东西两端无机碳体系各参数监测数值的差异明显大于海峡北部的主要原因。     

长江口邻近海域溶解态铝的分布及季节变化

基于2006年6、8、10月对长江口邻近海域的大面调查资料,分析了溶解态Al的分布及季节变化,讨论了水团混合、悬浮颗粒物及浮游植物水华对溶解态铝分布的影响。结果表明,3个航次溶解态铝的水平分布规律相似,都是近岸浓度最高,随着离岸距离的增加浓度降低,6、8、10月溶解态Al的平均浓度分别为(119±77)、(109±80)和(138±73)nmol/L,统计结果表明该海域的溶解态铝具有明显的季节变化。影响溶解态铝分布的主要因素有水团混合、底沉积物的再悬浮以及浮游植物的调节作用。     

2006年夏冬季长江口、杭州湾及邻近海域表层海水溶解态重金属的平面分布特征

利用2006年夏、冬季两个航次采集的长江口、杭州湾及邻近海域表层海水水样,分别采用石墨炉无火焰原子吸收分光光度法和火焰原子吸收分光光度法,测定了海水中溶解态Cu、Pb、Cd、总Cr的含量以及溶解态Zn的含量,研究了该海域表层海水中溶解态Cu、Pb、Zn、Cd和总Cr的平面分布状况,结果表明:(1)夏季表层海水中溶解态Cu、Pb、Zn、Cd和总Cr的平均质量浓度分别为0.90、0.54、5.80、0.080和0.46 μg/dm3;冬季则分别为1.01、0.81、9.32、0.070和0.31 μg/dm3,上述重金属元素含量基本达到国家一类海水水质标准,仅夏、冬季Pb的部分站位以及冬季Zn的部分站位达到国家二类海水水质标准.(2)表层海水溶解态Cu、Pb、Zn的质量浓度总体平面分布规律为:冬季高于夏季;Cd和总Cr的质量浓度总体平面分布规律为:夏季高于冬季.(3)影响近岸海域表层海水溶解态重金属分布的因素比较复杂,入海径流和排污口等输入海域的重金属对海水表层的重金属分布具有决定性的作用,同时,盐度、pH值、悬浮颗粒物质、营养盐等也是重要的影响因子.     

长江口及邻近海域夏季溶解无机碳体系及其响应机制初探

根据2009年8月“908”项目长江口补充调查总碱度(TAlk)、溶解无机碳(DIC)、pH值、溶解氧(DO)和叶绿素a(Chla)等数据的分析结果显示,长江口及邻近东海海域夏季溶解无机碳(DIC)含量分布范围在1 647.1～2 236.9 μmol/dm3之间,平均值为2 031.2 μmol/dm3;空间分布为由...     

长江口及邻近海域现代生物扰动构造定量表征及影响因素

生物扰动构造是表征海底环境状态的重要指标,是古沉积环境重建的主要依据,且它影响沉积物早期成岩作用以及物质的再分配,成为百年尺度沉积记录解读的干扰因素。本文基于长江口及其邻近海域的21个站位的沉积物岩心,利用高分辨X射线计算机断层扫描技术,通过matlab的数据处理,定性和定量表征了该区生物扰动构造,分析了影响生物扰动构造的主要因素。研究表明：长江口及邻近海域生物扰动构造较为发育,从功能上划分为生物扩散构造、运输构造、交换构造和廓道扩散构造4种类型,运输构造和廓道扩散构造常见;生物扰动构造在岩心中分布形式多样,包括指数衰减型、波动衰减型、均匀分布型、脉冲分布型等垂向分布形式;扰动深度深浅不一,多数在20 cm以内,但也有超过40 cm者;生物扰动构造空间上不均一,长江口及内陆架较发育,扰动构造体积在0～13 972 mm³之间,而苏北沿岸、中陆架则较少,扰动构造体积在351～3 212 mm³之间,从岸向外生物扰动构造有减少趋势。生物扰动构造发育程度主要受底质类型、沉积速率制约,黏土质粉砂以及适宜的沉积速率（0.52～1.34 cm/a）有利于生物扰动构造发育和保存。     

长江口及邻近海域夏季表层沉积物中重金属等的分布、来源与沉积物环境质量

通过现场调查研究报道了长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布、来源以及沉积物环境质量.结果显示,长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布很不均匀,除硫化物外,重金属、有机碳、石油类以及氮磷基本呈现长江口和杭州湾东北近岸的上海外海出现高值,其他区域浓度较低...     

长江口邻近海域余流的基本特征分析

根据2005年7月、2005年11月和2006年5月在长江口及其邻近海域进行的大范围水文调查资料,深入分析该海域余流的平面分布,垂直变化,大、小潮变化,季节变化等特征。结果表明,所测区域影响余流的因素很多,有底形、斜压、径流量、风应力、底摩擦、台湾暖流、浙江沿岸流、江苏沿岸流以及各因素间的相互作用。     

长江口邻近海域海水pH的季节变化及其影响因素

基于对2015—2016年长江口邻近海域现场调查数据的分析,探讨了其海水pH的季节变化和影响因素。结果表明:长江口邻近海域四季pH在7.76—8.32之间,其中夏季最高,秋季最低;夏季具有明显的分层现象,冬季水体pH垂直分布相对均一。长江冲淡水对长江口邻近海域水体pH的影响是局域性的。浮游植物光合作用是影响春、夏、秋季海水pH区域分布的重要过程。春、冬季节表层海水pH分布受海-气界面CO2交换的影响较大。温度、生物作用及长江冲淡水扩展是导致长江口邻近海域表层海水pH季节变化的主要因素。     

长江口及邻近海域有色溶解有机物的分布及河口混合行为的季节变化研究

于2019年3月、7月和10月对长江口及邻近海域有色溶解有机物(CDOM)的分布及河口混合行为进行分析研究。通过对盐度、吸收光谱斜率S_275～295、吸收系数a_CDOM(355)以及叶绿素a的分析发现,在河口内低盐度区,7月淡水流量大,陆源输入量最大,a_CDOM(355)值最高,3月CDOM来源主要受陆源输入和浮游植物生产活动的影响,a_CDOM(355)值较10月高;在口外高盐度区,3月和7月的a_CDOM(355)值相近,均低于10月,CDOM分布主要受浮游植物生产活动的影响。利用三维荧光光谱−平行因子分析方法共鉴定出4个荧光组分：类蛋白质组分C1(280/330 nm)、类腐殖质组分C2(300/350 nm)、类腐殖质组分C3(260/465 nm)和类腐殖质组分C4(320/410 nm)。在3月、7月及10月,4个荧光组分强度由长江口内到口外呈递减趋势,受陆源输入和浮游植物生产活动的影响,平均荧光强度的季节变化总体上来说,由大到小依次为7月、10月、3月。3个季节CDOM荧光组分均存在偏离理论稀释线的现象,说明CDOM的来源(陆源输入、沉积物再悬浮和现场生物活动)和去除(被颗粒物吸附、光降解和细菌降解)机制复杂多变,揭示了长江口区域CDOM在不同时空下的不保守混合行为。     

The partial pressure of carbon dioxide and air-sea fluxes in the Changjiang River Estuary and adjacent Hangzhou Bay

The distributions of partial pressure of carbon dioxide (p CO2 ) in the surface waters of the Changjiang River Estuary and adjacent Hangzhou Bay were examined in the summer of 2010. Surface water p CO2 ranged from 751-2 095 μatm (1 atm=101 325 Pa) in the inner estuary, 177-1 036 μatm in the outer estuary, and 498-1 166 μatm in Hangzhou Bay. Overall, surface p CO2 behaved conservatively during the estuary mixing. In the inner estuary, surface p CO2 was relatively high due to urbanized pollution and a high respiration rate. The lowest p CO2 was observed in the outer estuary, which was apparently induced by a phytoplankton bloom because the dissolved oxygen and chlorophyll a were very high. The Changjiang River Estuary was a significant source of atmospheric CO2 and the degassing fluxes were estimated as 0-230 mmol/(m2 d) [61 mmol/(m2 d) on average] in the inner estuary. In contrast, the outer estuary acted as a CO2 sink.     

Indicators and impact analysis of sediment from the Changjiang Estuary and East China Sea to the Hangzhou Bay

Based on the historical evolution of the Hangzhou Bay, by making use of the conclusions made by the previous research workers and the integration of concrete data, five distinct impact indicators of the sediment from the Changjiang Estuary and the East China Sea to the Hangzhou Bay are summarized. Numerical calculation and analysis indicate that the scouring and deposition of seabed in the Hangzhou Bay are subject to the direct impact of the evolution of the Changjiang Estuary, and the growth and decline and the direction of the sandy bar at Nanhuizui give traces to the sediment transport between the Changjiang Estuary and the Hangzhou Bay. The transport of sediment from the Changjiang Estuary to the Hangzhou Bay occurs mainly in winter and spring seasons and the increase of the Changjiang River runoff and the decrease of sediment charge have caused scouring in the northern coast of the Hangzhou Bay and the seabed erosion along the frontal margin of the Changjiang River Delta.     

Indicators and impact analysis of sediment from the Changjiang Estuary and East China Sea to the Hangzhou Bay

Based on the historical evolution of the Hangzhou Bay, by making use of the conclusions made by the previous research workers and the integration of concrete data, five distinct impact indicators of the sediment from the Changjiang Estuary and the East China Sea to the Hangzhou Bay are summarized. Numerical calculation and analysis indicate that the scouring and deposition of seabed in the Hangzhou Bay are subject to the direct impact of the evolution of the Changjiang Estuary, and the growth and decline and the direction of the sandy bar at Nanhuizui give traces to the sediment transport between the Changjiang Estuary and the Hangzhou Bay. The transport of sediment from the Changjiang Estuary to the Hangzhou Bay occurs mainly in winter and spring seasons and the increase of the Changjiang River runoff and the decrease of sediment charge have caused scouring in the northern coast of the Hangzhou Bay and the seabed erosion along the frontal margin of the Changjiang River Delta.     

Grain size composition and transport of sedimentary organic carbon in the Changjiang River (Yangtze River) Estuary and Hangzhou Bay and their adjacent waters

Surface sediments from the Changjiang River(Yangtze River) Estuary,Hangzhou Bay,and their adjacent waters were analyzed for their grain size distribution,organic carbon(OC) concentration,and stable carbon isotope composition(δ13C).Based on this analysis,about 36 surface sediment samples were selected from various environments and separated into sand(0.250 mm,0.125–0.250 mm,0.063–0.125 mm) and silt(0.025–0.063 mm)fractions by wet-sieving fractionation methods,and further into silt-(0.004–0.025 mm) and clay-sized(0.004mm) fractions by centrifugal fractionation.Sediments of six grain size categories were analyzed for their OC andδ13C contents to explore the grain size composition and transport paths of sedimentary OC in the study area.From fine to coarse fractions,the OC content was 1.18%,0.51%,0.46%,0.42%,0.99%,and 0.48%,respectively,while theδ13C was –21.64‰,–22.03‰,–22.52‰,–22.46‰,–22.36‰,and –22.28‰,respectively.In each size category,the OC contribution was 42.96%,26.06%,9.82%,5.75%,7.09%,and 8.33%,respectively.The OC content in clay and fine silt fractions(0.025 mm) was about 69.02%.High OC concentrations were mainly found in offshore modern sediments in the northeast of the Changjiang River Estuary,in modern sediments in the lower estuary of the Changjiang River and Hangzhou Bay,and in Cyclonic Eddy modern sediments to the southwest of the Cheju Island.Integrating the distribution of terrestrial OC content of each grain size category with the δ13C of the bulk sediment indicated that the terrestrial organic material in the Changjiang River Estuary was transported seaward and dispersed to the Cyclonic Eddy modern sediments to the southwest of the Cheju Island via two pathways:one was a result of the Changjiang River Diluted Water(CDW) northeastward extending branch driven by the North Jiangsu Coastal Current and the Yellow Sea Coastal Current,while the other one was the result of the CDW southward extending branch driven by the Taiwan Warm Current.     

长江口和杭州湾海域生物生产力锋面及其生态学效应

通过分析海洋生态学资料并结合卫星遥感、渔场及赤潮等资料,发现长江口和杭州湾及其毗邻海域生物生产力的锋面,在离长江口门和杭州湾口约100 km的长江冲淡水中部海域出现蓝细菌丰度、浮游植物现存量和初级生产力以及浮游动物的最大值,该锋面的存在和位置被水色遥感所确认.光和营养盐在此呈现最佳的权衡.在该锋区悬浮体浓度小于5 mg/dm3,盐度为25～30.在该锋面的西侧高的悬浮体浓度造成了浮游植物的光限制,其东侧距长江口和杭州湾口较远,陆源营养盐被稀释,加之浮游植物的消耗,造成了营养盐的限制.夏季水体的层化,增强了水体的垂直稳定,使这种分布格局更加显著.由于细菌多附着在悬浮颗粒物的表面,细菌丰度的最大值出现在近口门区的最大浊度带,在向外海方向随着悬浮体的沉降细菌丰度迅速降低.在生物生产力锋面,浮游植物的旺发导致水体跃层之上高溶解氧浓度和低营养盐浓度,尤其是PO4被耗尽,同时浮游动物饵料的丰富,造成浮游动物旺发;由于蓝细菌的快速增殖,其流式细胞测定的细胞粒径变小.生物生产力锋面的出现产生了显著的生态学效应,一方面造成某些经济鱼类产卵和索饵场的形成,例如鲐鲹鱼、马鲛鱼等;另一方面造成赤潮多发区和底层水缺氧区.     

灰色聚类法评价长江口、杭州湾海域表层海水中的重金属污染程度

通过2007年秋季航次我国近海海洋环境的综合调查,研究了长江口与杭州湾海域表层海水中重金属汞、砷、铜、铅、锌、镉、总铬的含量与分布,利用灰色聚类法对海水中的重金属元素进行评价。参照《国家海水水质标准GB3097-1997》,通过灰类白化权函数确定海水水质分级界限及各参评指标对不同等级的聚类权,构建了海水中重金属的灰色聚类法综合评价模型。该模型能够较客观、合理地评价海水中的重金属。评价结果表明,长江口与杭州湾海域表层海水中的重金属总体情况良好,但是汞、铅含量偏高,尤其是汞。长江口外以北、杭州湾北岸口外及舟山群岛邻近海域的海水水质相对较差,陆源排污为主要影响因子。     

Numerical study on residual current and its impact on mass transport in the Hangzhou Bay and the Changjiang Estuary I. A3-D joint model of the Hangzhou Bay and the Changjiang Estuary

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Numerical study on residual current and its impact on mass transport in the Hangzhou Bay and the Changjiang Estuary Ⅰ.A3-D joint model of the Hangzhou Bay and the Changjiang Estuary

A 3-D numerical model is set up in a large domain covering the Hang zhou Bay and the Changjiang Estuary based on the ECOM model in orthogonal curvilinear coordinates.The numerical schemes for baroclinic pressure gradient (BPG) terms and convective terms are improved in the paper according to the characteristics of velocity field and mass transport in the area.The model is validated by the simulations of residual current and salinity transport in the Hangzhou Bay and the Changjiang Estuary.