Spatiotemporal changes of biogenic elements in the Changjiang River Estuary and adjacent waters in summer over the last decade

The long-term spatiotemporal changes of surface biogenic elements in the Changjiang River Estuary and adjacent waters during the summer of 2008-2016 were analyzed in this study.The concentrations of dissolved inorganic nitrogen(DIN),soluble reactive phosphate(PO₄^3-) and silicate(SiO₃^2-) were generally stable,with a slight decrease of DIN and PO₄^3-,and a slight increase of SiO₃^2-,which mainly occurred in the e...     

长江口稀土元素地球化学特征

河口地区是陆海相互作用最具特色的典型区域,这里陆地与海洋之间的物质和能量交换迅速,物理、化学和生物学过程之间的相互作用极其复杂,对河流迁移的化学信号起着过滤器的作用[1].利用稀土元素(REEs)化学性质相似而又有系统差别的特点可以进行河口区河海相互作用过程的地球化学研究[2].准确测定河口区溶解态、胶体态、悬浮颗粒态、沉积物态以及生物体中REEs是研究河海相互作用的关键.随着现代仪器分析技术的发展,准确测定河海相互作用过程中不同相态尤其是水体溶解态超痕量稀土元素含量成为可能[3~7],从而使稀土元素地球化学,尤其是河口稀土元素地球化学的研究得以深入[8~16].     

长江口及邻近海域表层水体溶解氧饱和度的季节变化和特征

根据“908”ST04区块调查的夏、冬、春、秋季四个航次和“908”补充调查的8月航次资料对长江口及邻近海区表层水体溶解氧及其饱和度进行了探讨.研究表明东海北部表层水体在夏季和春季以浮游植物光合作用为主要控制过程,特别是7、8月份长江口外、杭州湾外及浙江近海存在大范围的强光合作用区;秋季以有机质氧化分解过程为主,表层溶...     

长江口及其邻近海域溶解硒的地球化学控制过程研究

Dissolved selenium in the Changjiang(Yangtze) Estuary and its adjacent waters was determined by hydride generation atomic fluorescence spectrometry to elucidate the source, behavior in estuary, adsorption-desorption process and biological role. In surface water, Se(IV) concentration ranged 0.05–1.14 nmol/L and Se(VI) concentration varied 0.01–1.20 nmol/L, with the means of 0.76 and 0.49 nmol/L, respectively. In bottom water, Se(IV) content varied 0.03–0.27 nmol/L and Se(VI) content ranged 0.04–0.85 nmol/L, with the averages of 0.10 and 0.40 nmol/L, respectively. High level of Se(IV) was observed near the shore with a significant decrease towards the open sea, suggesting the continental input from the adjacent rivers. Large value of Se(VI) was found in bottom water, reflecting the release from suspended sediment. Besides, high value appeared in the same latitude of the Changjiang Estuary and Hangzhou Bay illustrated the effect of lateral mixing and the long-distance transport of selenium. Se(VI), more soluble, occupied higher percentage in aqueous environment. The presence of Se(IV) resulted from the degradation of residue and the reduction of Se(VI) under anaerobic condition. The positive relationship to suspended particulate material(SPM) and negative correlation to depth indicated that Se(IV) tended to be released from the high density particulate matter. Instead, Se(VI) content did not significantly relate to SPM since it generally formed inner-sphere complex to iron hydroxide. Se(IV) content negatively varied to salinity and largely depended on the freshwater dilution and physical mixing. While, Se(VI) level deviated from the dilution line due to the in situ biogeochemical process such as removal via phytoplankton uptake and inputs via organic matter regeneration. As the essential element, Se(IV) was confirmed more bioavailable to phytoplankton growth than Se(VI), and moreover, seemed to be more related to phosphorus than to nitrogen.     

长江口及其邻近海域2012年3月和7月溶解态铝的分布特征分析

分别于2012年3月和7月对长江口及其邻近海域水体中溶解态铝的分布及其影响因素进行了研究,并在2012年3月至2013年11月期间对长江徐六泾进行了连续观测。结果表明,徐六泾溶解态铝在夏季出现最高值,在冬季呈现最低值,平均值分别为(313±130)nmol/L和(140±43)nmol/L,表现出与径流量相似的季节变化规律。受陆源输入变化的影响,长江口溶解态铝的浓度由近岸向外海逐渐降低,且呈现出明显的季节性差异,即7月明显高于3月。3月表、底层海水中溶解态铝的浓度范围分别为21~129 nmol/L和27~146 nmol/L,平均值分别为(49±21)nmol/L和(59±27)nmol/L;7月表、底层溶解态铝的浓度范围分别为6~332 nmol/L和9~252 nmol/L,平均值分别为(66±69)nmol/L和(83±74)nmol/L。在7月,表、底层溶解态铝呈现显著性差异,底层沉积物的再悬浮可能是造成差异的主要原因。调查结果表明,溶解态铝在长江口呈现出清除型行为,清除主要发生在咸淡水混合初期,初步计算出7月份溶解态铝的清除率约为55%。     

Relationship between biogeochemical features of biogenic elements and flocculation in the Changjiang Estuary

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九龙江河口区稀土元素地球化学特征

用电感耦合等离子体质谱（ICP-MS）对2007年10月航次采集的九龙江河口区溶解态、悬浮颗粒态、沉积物样品中的稀土元素（REEs）进行了测定,对REEs的地球化学特征进行研究.结果表明,REEs在各相态中的含量范围如下：溶解态的为0.1 ng/dm^3（Eu）～1.96μg/dm^3（Ce）,悬浮颗粒态的为0.28（Tm）～142.83（Ce）mg/kg,沉积物的为0.25（Tm）～99.65（Ce）mg/kg;溶解态、悬浮颗粒态及沉积物中REEs球粒陨石标准化配分曲线均表现为负斜率型,九龙江河口为LREE相对HREE富集型河口.九龙江河口溶解态、悬浮颗粒态、沉积物三相态中REEs含量受流域土壤、地表径流等源区因素影响较大.Ce异常值在各相态中表现为负异常.     

长江口及邻近海域浮游端足类分布特征

根据2002—2003年长江口28°00'~32°00'N,122°00'~123°30'E海域4个季节的海洋调查数据,运用定量、定性方法探讨了长江口及邻近海域浮游端足类总丰度的平面分布、季节变化及与渔场的关系,分析了优势种的数量变动和对浮游端足类总丰度的贡献,并与东海外海种类的生态特征做了比较。结果表明,长江口及邻近海域浮游端足类丰度季节变化主要受温度的影响,而平面分布变化则与盐度相关。平均丰度在夏季最高(2.75个/m3),在冬季最低(0.10个/m3)。本次调查共发现浮游端足类49种,江湖独眼钩虾(Monoculodes limnophilus)和裂颏蛮(Lestrigonus schizogeneios)是最主要的优势种,江湖独眼钩虾在四季中对端足类总丰度都有很大贡献,在春秋冬三季为第一优势种,说明江湖独眼钩虾对相对较低的温度具有一定的适应能力,裂颏蛮则只在春夏秋季有较大贡献,其中夏季裂颏蛮贡献率为0.87,高于江湖独眼钩虾,这与裂颏蛮具有较高温度的环境适应能力有关。浮游端足类种类数与总丰度都与表层温度的线性相关显著,同表层盐度的相关不显著。作为长江口鱼类的重要饵料之一,浮游端足类的数量分布对长江口和舟山海域渔场的形成有重要的意义。     

Taxonomic diversity of fish assemblages in the Changjiang Estuary and its adjacent waters

Taxonomic diversity of fish assemblages in the Changjiang Estuary(Yangtze River Estuary) and its adjacent waters was analyzed based on bottom trawl surveys carried out by R/V Beidou in June,August and October 2006.Four groups of fishes were identified for each survey by the twoway indicator species analysis(TWIA).Taxonomic distinctness,species richness and phylogenetic diversity were used to detect changes in taxonomic structure of fish assemblages.Most dominant fish species mainly belonged to Perciformes,Pleuronectiformes,Clupeiformes,Scorpaeniformes and Tetraodontiformes.Species richness in offshore waters of the survey area was higher than that in the other area.The average taxonomic distinctness value(AvTD,△+ ) of each fish assemblage was close to the average taxonomic distinctness of master list in the Changjiang Estuary(79.9),and had a positive correlation with species richness and Shannon diversity index(H ).A negative correlation was found between variations in taxonomic distinctness(VarTD,Λ + ) and traditional diversity indices,which were caused by fish species component that led to longer average path lengths among species.Taxonomic diversity index(△) had the similar results with species richness,H ,Simpson diversity index(D) and Pielou's evenness index(J ).VarTD also kept stable,which further certificated that fish assemblages and ecological environment were in equilibrium.Taxonomic distinctness index(△* ) was relatively stable in most of fish assemblages,and had higher values in some fish assemblages for a few absolutely dominant species.The present study showed that fish community formed new equilibrium stability in 2006 in the Changjiang Estuary when compared with those in the corresponding months of annual survey from 1985 to 1986.And AvTD in each sampling station was lower than AvTD of master list in the Changjiang Estuary,so some ecological niches were absent in each sampling stations from taxonomic or phylogenetic relationships,these would be helpful to stock natural resource and maintain ecological equilibruim of fish assemblages.     

Macrobenthic community structure in the Changjiang Estuary and its adjacent waters in summer

On the basis of data collected in the summer of 2006 from 27 sampling stations in the Changjiang Estuary and its adjacent waters, the ecological characteristics of macrobenthos and the relationship between the macrobenthos and the environmental factors were studied using hierarchical cluster and non-metric multidimensional scaling (MDS).The biomass, abundance, Shannon-Wiener's and Margalef's indices of the macrobenthos were presented. The results showed that a total of 253 macrobenthic species were found in the research region, and most of them belong to mollusks and polychaetes. The dominant species were Cossurella dimorpha, Eocylichna cylindrella, Episiphon kiaochowwanense, Nassarius semiplicatus, Ocstergrenia variabilis and Sternaspis scutata. The average abundance of the macrobenthos was (313.15±233.4) ind./m2, and the average biomass was (15.2±11.2)g/m2.The distribution patterns of the abundance and biomass of the macrobenthos were similar. The abundance and biomass in the area close to the estuary were lower than those from the area more distant to the estuary; the central part of the research region had higher abundance and biomass than other parts of the research region. In accordance with the results, four macrobenthic communities with distinct spatial differences were identified. The low abundance and biomass in the area close to the estuary should be caused by the high sedimentation rate. The statistical analysis indicated that the depth is the most important factor affecting the distribution of macrobenthos.     

长江口及杭州湾邻近海域夏季表层海水中的溶解无机碳

根据2004年8月在长江口、杭州湾附近海域获得的调查资料对表层水中Ph值、总碱度和溶解无机碳的分布特征及其与环境参数的关系进行了研究,并由此得到了溶解无机碳的组成情况.结果表明,HCO3-、CO23-;和CO2(T)占溶解无机碳浓度百分比分别为80.33%～97.75%、0.61%～19.42%和0.25%～2.34%,平均值分别为(93.28±3.68)%、(5.58±4.03)%和(1.14±0.43)%.水文、浮游植物等对各参数的分布具有重要影响,但对不同参数的影响程度不同.     

Temporal and spatial distribution of dissolved copper, lead, zinc and cadmium in the Changjiang Estuary and its adjacent waters

Heavy metal concentrations were measured in the Changjiang Estuary and its adjacent waters. Results from a systematic survey in April 2002 to March 2003 indicate that the ranges of the concentrations of dissolved copper, lead, zinc and cadmium in the study waters are 1.01 - 6.86, 0. 10 - 0.39,3.17 - 9.12 and 0.011 - 0. 049 μg/dm^3 , respectively. Similar to zinc, the behavior of dissolved copper was essentially conservative, but high scatter has been observed for high salinity samples, which can be attributed to the decomposition or mineralization of organic matter by bacteria. Dissolved lead may have active behavior with an addition at high salinity. Overall concentrations of dissolved cadmium increase with salinity. The mean values of these dissolved metals calculated for the surface waters were higher than those for the middle and bottom ones. External inputs of dissolved heavy metals to the surface waters were the likely explanation for these higher values. The maximum seasonal average values of dissolved copper and zinc were found in summer, reflecting higher amounts of riverine input in this season. In contrast, the maximum seasonal average values of dissolved lead and copper were found in winter and the lowest ones in summer, respectively, which might be asso- ciated with a combination of low concentration with heterogeneous scavenging. Concentrations of these dissolved metals found for the Changjiang Estuary fall in the range observed for the other estuaries but are noticeably higher than those from uncontaminated rivers, except for cadmium. Compared with observations for the Changjiang Estuary in the last two decades, it is clear that the Changjiang estuarine waters has been contaminated with copper, lead, zinc and cadmium during China＇ s industrialization, but concentrations of them have decreased in the last few years.     

大沽河流域地下水中稀土元素的地球化学特征

近岸地下水排泄是近海稀土元素的重要来源,目前对地下水中稀土元素的地球化学行为的认识还十分有限。本文通过现场调查和模拟计算对山东大沽河流域地下水中溶解态稀土元素的分布、影响因素及络合形态进行了研究。结果表明：稀土元素在地下水中的分布具有较大的空间差异,pH和铁锰氧化物/氢氧化物的还原性溶解是影响稀土元素含量的重要因素。稀土元素的络合形态以LnCO+3和Ln(CO3)-2为主,但是在硫酸根含量较高的情况下,轻稀土较中稀土和重稀土更易于形成LnSO+4。大沽河流域地下水表现为重稀土富集,含水层中负电荷颗粒物对LnCO+3的优先吸附可能是富集的原因。受周边炼油厂影响,所有样品中的La均表现为正异常,人为源La在地下淡水和再循环海水中所占比例分别为34%~75%和42%~57%。     

长江口海域表层沉积物常量元素地球化学及其地质意义

通过对长江口外海域187个表层沉积物样品进行常量元素氧化物(SiO₂,Al₂O₃,Fe₂O₃,MgO,CaO,Na₂O,K₂O,P₂O₅,TiO₂,MnO,TOC和 CaCO₃)测试,分析其空间分布特征及其地质意义。结果显示,研究区表层沉积物常量元素氧化物主要由SiO₂,Al₂O₃,Fe₂O₃,MgO,CaO,Na₂O,K₂O和TiO₂等组成,这8种组分约占沉积物总量的91.59%;其中SiO₂和Al₂O₃含量最高,平均值分别为62.43%和11.16%。R型因子分析结果表明,研究区表层沉积物的常量元素氧化物可以分为3类:第1类包括SiO₂,Al₂O₃,Fe₂O₃,MgO,P₂O₅,TiO₂和MnO;第2类包括CaO,K₂O,CaCO₃和TOC;第3类包括Na₂O,这3类可能分别代表了陆源碎屑沉积、海洋生物和陆源混合沉积以及海洋化学沉积。Al₂O₃/Na₂O和CIA的空间分布较为相似,指示了长江入海物质主要堆积在长江口及其以南的123.5°E以西海域,闽浙冬季沿岸流是其主要驱动力。     

Delineating suspended sediment concentration patterns in surface waters of the Changjiang Estuary by remote sensing analysis

Three Landsat TM imageries (taken on 18 May 1987, 4 August 1998 and 28 July 2007) were used as the data source to identify the spatial and temporal variations of the suspended sediment concentration (SSC) in surface waters of the Changjiang Estuary. Atmospheric correction was carried out to determine the water-leaving reflectance using the FLAASH module. A regression equation between surveyed SSC and suspended sediment index was chosen to retrieve the SSC from the Landsat TM images. In addition, tidal harmonic analysis was performed to calculate tidal conditions corresponding to the acquisition time of satellite images. The results show that the SSC spatial patterns are similar to the in situ observation results, which show the highest SSC in the region of turbidity maximum zone in the Changjiang Estuary. For the period of 1987 to 2007, the SSC pattern is controlled mainly by tidal dynamic conditions and wind speeds, rather than sediment discharges from the river.     

On new species and records of Hydroidomedusae from the Changjiang River Estuary and its adjacent waters

1 IntroductionSamples of medusae collected from 37 stationsof the Changjiang River Estuary ( 28°0. 00′~32°19.60′N,121°6.52′~124°0.00′E) during14 ~16 June 2003,Altogether,164 qualitative andquantitative samples of the plankton are analyzed,and 49 s     

夏季长江口海域溶解态铁的分布及混合行为研究

本文基于2015年7月长江口的现场调查资料,分析讨论了长江河口区溶解态铁(DFe)的含量分布与混合行为及其影响因素。结果表明:长江径流携带大量的DFe入海,且口内区(Ⅰ)浓度高于混合区(Ⅱ)和外海区(Ⅲ),平均浓度分别为166.45±6.26nmol/L,14.04±8.80nmol/L和6.18±1.51nmol/L。受去除作用和海水稀释的影响,在河口区DFe的浓度下降率达到96.92%。DFe浓度与盐度的关系符合指数模型,由模型与理论稀释线估算的长江口海域DFe的理论最大去除率为97.75%,与实际测得的最大浓度下降率相近。长江冲淡水、苏北沿岸流和台湾暖流影响DFe的水平分布。受长江冲淡水影响,长江口外海域DFe浓度高达176.50nmol/L。苏北沿岸流主要影响研究区域北部的表层水,其携带的DFe浓度低于长江冲淡水。台湾暖流是导致研究区域东南部DFe浓度较低的主要原因,使得中层和底层水中浓度分别低至4.04nmol/L和4.79nmol/L。另外,在表层海水中DFe的分布受到叶绿素a、溶解有机碳和溶解氧的共同影响,DFe与叶绿素a、溶解氧呈显著负相关,与溶解有机碳呈显著正相关。     

长江口及其邻近海域水螅水母纲新种和新记录记述

长江口及其邻近海域水螅水母纲有49种,隶属于26科,34属,其中有2个新种:瓣高手水母(Bougainvillia lamellata n.sp.)、单管玛拉水母(Malagazzia monocanalis n.sp.)和2种我国新记录:橙黄高手水母(Bougainvillia aurantiaca Bouillon,1980)、玫瑰太阳水母[Solmaris rhodolma(Brandt,1838)],此外,我国记载的束状高手水母[Bougainvillia ramosa(van Beneden,1844)]订正为鳞茎高手水母(B.muscus(Allman,1863)).     

Spatial variations of rare earth elements in north pacific surface water

The concentration of dissolved rare earth elements (REE) were determined at 47 stations in the North Pacific surface waters. Combining with other previous data, we present the surface REE distribution in the North Pacific and discuss the controlling factors. The surface concentrations increase toward the high latitude and continental margin (e.g. [Nd] > 10 pmol kg⁻¹) from the central North Pacific (e.g. [Nd] < 5 pmol kg⁻¹). The North Pacific Deep Water-normalized REE patterns are varied, indicating that two or more factors contribute to the REE distribution. We examined four factors making the regional variation of surface REE concentrations mainly; a) particle scavenging, b) atmospheric dust input, c) vertical mixing and d) lateral transport from the coastal region. Flux calculations for Nd showed that the influence of atmospheric dust was less significant than the vertical input even in the western upwelling zone. Moreover, the longitudinal and latitudinal transitions of surface REE seem to reflect the lateral supply from the coastal areas. We constructed the diagram of surface Er/Lu and Er/Yb molar ratios in order to assess the origin and the input processes of the surface REE. Both molar ratios showed increasing trend toward PEW (Er/Lu (>10.5) and Er/Yb (>1.4)) from PSUW (Er/Lu (>7) and Er/Yb (>1.2)). The high Er/Lu and Er/Yb ratios in PEW indicate that the lateral supply of terrestrial materials from the coastal area is possibly the important factor in PEW, because only weathering and dissolution of rocks can explain such high Er/Lu and Er/Yb ratios to our knowledge.     

不同成因的海洋铁锰氧化物沉积物中稀土元素的地球化学特征

测试了具代表性的成岩型结核和水成型结壳的稀土元素,以研究稀土元素在这两种成因的海洋铁锰氧化物沉积物的特征及其与成因的关系。稀土元素特征表明稀土元素没有参与成岩型结核的成岩作用。即没有加入到1nm水锰矿中去,而是加入到无定形铁的氧化物、氢氧化物中去。同样,稀土元素也没有直接参与水成结壳的水成作用,即没有加入到锰、铁的氧化物、氢氧化物中去,而是与钙、磷相关。推测在很大程度上是先沉淀在钙、磷相中然后才加入到水成结壳中。稀土元素在这两种类型的沉积物的分布与其成因密切相关。