中全新世以来东海内陆架泥质沉积物来源

利用判别函数、Eu异常与稀土元素总量关系(δEuN-ΣREEs)图解以及物源定量识别方法,对位于浙闽沿岸泥质带的EC2005孔常微量、稀土元素地球化学进行分析,利用14C测量加速器质谱仪(AMS14C)进行年龄测定,探讨东海内陆架EC2005孔泥质沉积物来源。结果表明:EC2005孔泥质沉积物主要来源于长江,其平均贡献量为93.7%,没有识别出黄河物质;历史时期黄河物质可以影响到29°N甚至于更为偏南的区域(南界为27°25’N),台湾海峡西北部则可以接受台湾物质的输入;浙闽沿岸泥质区物质来源具有一定的复杂性,值得进一步深入研究。     

Observation of small-scale processes over shelf break in the East China Sea

The turbulent dissipation along with temperature and salinity was measured on board R/V Dong Fang Hong 2 over the shelf break of the East China Sea from March 7 to 9, 2004. Applying the Turner angle, it is found that the ＇diffusive＇ double diffusion, salt-fingering, and stable stratification coexist in the upper water column of about 50 m. Below that depth, there exists weak salt-fingering. The turbulent dissipation rates are enhanced along the ray paths of M2 internal tides emanating from the shelf break with values ranging from 1.0×10^-9 W·kg^-1 to 1.2×10^-6 W·kg^-1. The corresponding diapycnal mixing rates are from 1×10^-6 m^2· s^-1 to 1×10^-2 m^2· s^-1. The spatially averaged mixing rate over the whole observation section is 2.3×10^-3 m^2· s^-1, which is much larger than 1×10^-5 m^2·s^-1 of the background diapycnal mixing rate in the open ocean.     

Recent 2000-year geological records of mud in the inner shelf of the East China Sea and their climatic implications

AMS^14C dating and grain-size analysis for Core DD2, located at the north of the Yangtze River-derived mud off the Zhejiang-Fujian coasts in the inner shelf of the East China Sea, provide us a high-resolution grain-size distribution curve varying with depth and time. Data in the upper mud layer of Core DD2 indicate that there are at least 9 abrupt grain-size increasing in recent 2000 years, with each corresponding very well with the low-temperature events in Chinese history, which might result from the periodical strengthening of the East Asian Winter Monsoon (EAWM), including the first-revealed maximum temperature lowering event at around 990 a BP. At the same time, the finer grain size section in Core DD2 agrees well with the Sui-Tang Warming Period (600--1000 a AD) defined previously by Zhu Kezhen, during which the climate had a warm, cold and warm fluctuation, with a dominated cooling period of 750-850 a AD. The Little Ice Age (LIA) can also be identified in the core. It starts around 1450 a AD and was followed by a subsequent cooling events at 1510, 1670 and 1840 a AD. Timing of these cold events revealed here still needs to be further verified owing to some current uncertainty of dating we used in this study.     

Linear sand ridges on the outer shelf of the East China Sea

Based on the latest full-coverage high-resolution multi-beam sounding data, the distribution of the linear sand ridges on the outer shelf of the East China Sea （ECS） is studied with quantitative statistical analysis. The study area can be divided into the northeastern part and the southwestern part. Sand ridges in the northeastern area, trending 116°N, show obvious linear character and shrink to the inner shell Sand ridges in the southwestern area, trending 120°N -146°N, tend to have net form. Sand ridges gradually become sand sheets in the center part of study area. Sand ridges are distributed landward to the isobath of 60m, distributed seaward to the water depth of 120 m in the northeast and 150 m in the southwest. Immature sand ridges are observed at water depth of 130-180 m in the southwestern depressions. The acoustic reflection properties of the internal high.angle inclined beddings of the sand ridges are analyzed based on the typical seismic profiles close to the research area. Lithological analysis and dating of 4 boreholes and 12 cores indicate that the widely distributed transgressive sand layer with high content of shell debris which was formed in the early-middle Holocene is the main composition of the linear sand ridges on the outer shelf of the ECS. The dominating factor in formation, developing and burying of the sand ridges is the variation of water depth caused by sealevel change and the rate of sediment supply. In 12400 aBP the cotidal lines of the M2 tidal component were closely perpendicular to the strike-directions of the sand ridges in the study area, and the tidal wave system during 12000-8000 aBP might play a key role in the formation of the linear sand ridges which are widely distributed on the outer shelf of the ECS.     

长江口及其邻近海域近代沉积物中甲藻孢囊的垂直分布

于2005年4～5月,在长江口外及浙江中南部海域设置5个采样站点,获取了15～40 cm的沉积物柱状样,分层研究了甲藻(dinoflagellates)孢囊的垂直分布.在本研究中共鉴定出46种甲藻孢囊,其中自养型19种,异养型27种.长江口海域复杂的流系特征及环境状况对孢囊分布有明显影响,致使孢囊丰度较低,平均丰度为366.2cysts·g-1,且无明显垂直分布规律.锥状斯氏藻孢囊是最为丰富的自养型甲藻孢囊,平均质量分数介于17.0%～28.9%;异养型甲藻孢囊以原多甲藻属为主,平均质量分数为29.5%～53.6%,其它类型孢囊仅零星分布.有毒藻亚历山大藻孢囊在各站位均有分布,但丰度较低,最高值仅为68.1 cysts·g-1.     

东海细点圆趾蟹繁殖生物学的初步研究

根据2010—2011年在东海渔业生产采集的细点圆趾蟹样品,结合实验室养殖,开展了对其繁殖生物学的研究。结果表明：东海细点圆趾蟹交配时,以硬壳雄蟹与软壳雌蟹的配对组合较为常见。最小抱卵个体头胸甲甲长为32．15mm,甲宽为55．50mm,体重为45．46g。大部分抱卵个体的甲宽为60～75mm。当甲宽为55．50～80．12mm时,抱卵个体的抱卵量为（20．34～68．09）万,细点圆趾蟹的繁殖力随着雌性亲体规格的增大而增加。细点圆趾蟹的个体绝对繁殖力与甲宽的关系为：F=0．79L3102（R2=0．998）。相同规格的雌性亲体,抱卵量比成熟卵母细胞数量少,这表明在产卵与孵化过程中有卵子损失。     

A 200-ka carbon isotope record from the South China Sea

Stable isotope of autogenous oceanic carbonate (e.g., calcite of foraminiferal shells) has become a basic tracer in paleoceanography. Oxygen isotope composi-tion (δ 18O) is generally controlled by factors, such as ice volume and water temperature, and is…     

Mass-balance ecosystem model of the East China Sea

Using the Ecopath mass-balance trophodynamic model, this paper analyzed the trophic levels, flows, food web structure and ecosystem maturity of the East China Sea, and identified ecologically important functional groups in the ecosystem. The model is based on fishery resource surveys of the East China Sea in 2000, studies on diet composition and global databases such as FishBase and the Sea Around Us Project Database. The results showed that trophic levels of the functional groups are between 2.86 and 4.37, with an average of 3.32. Anchocy (Engraulis japonicus), small fishes and benthic crustaceans such as shrimps and crabs are important groups in terms of the trophic structure and flow dynamics in the East China Sea. Energy flows of most groups are between specific trophic levels, except file fish (Thamnaconus spp.), pomfret (Pampus spp.) and cephalopods. Trophic transfer efficiency of levels II, III, IV and more than V are 11.8%, 21.1%, 17.4% and 22.1–22.5%, respectively. Effects of fishery – the largest ‘consumer’ of the ecosystem – are much stronger than those exerted by biological groups in the system. The model suggests that the current fishery can further reduce the complexity of the ecosystem. Evaluations of the system indices suggest that maturity of the ecosystem is low. The conclusion of this model indicates that it was the overfishing that caused the ecosystem of the East China Sea declined, which should be taken into account as a critical reference for fisheries management in the future.     

黑碳对沉积物和土壤中乙草胺吸附作用

黑碳是自然界普遍存在的物质,它对持久性污染物的迁移转化有重要影响.研究了沉积物和土壤中的黑碳在农药乙草胺吸附行为中的作用.结果表明:乙草胺在黑碳上的初始吸附符合一级动力学模型.在黑碳与有机碳相对含量较低(fBC/fOC=0.02～0.09)时,非黑碳的有机碳对吸附起主要作用.在黑碳与有机碳的相对含量较高(0.30～0.61)时,黑碳对吸附起主导作用,黑碳相对含量越高,对KOC影响越大.同时,建立了乙草胺吸附体系中KOC与fBC之间的关系模型用于预测不同黑碳含量的天然吸附剂对乙草胺的吸附能力.     

近8 ka东亚冬季风记录在东海内陆架的建立

目的在于尝试从东海内陆架上建立全新世高分辨率的东亚冬季风替代性序列.通过对位于东海内陆架闽浙沿岸泥质中部的PC-6孔(740 cm)进行AMS14C年龄测试和粒度分析,综合沉积构造、沉积层序与海平面变化讨论该孔的沉积环境,其上(0~450 cm)、中(450~540 cm)、下(540~740 cm)段分别对应于前滨、近滨和与现今环境基本一致的浅海沉积环境,其中上段的沉积作用主要受控于东海冬季沿岸流.通过计算该孔的粒级-标准偏差,提取了环境敏感粒度组分,该孔沉积物粒度由以28μm为界的2个粒度子体构成,它们的峰值即约5~6μm与102~125μm分别为对应于冬季沿岸流和波浪的敏感粒级;细粒组分(<28μm)对应于沿岸流,为沿岸流所携带,表现为平行于海岸的横向迁移,粗粒组分对应于波浪,沉积物以垂直于海岸的纵向迁移为主.PC-6孔上段细粒组分的含量一般在85%以上,利用其平均粒径序列建立了研究东亚冬季风演化的替代性序列.     

东、黄海典型海区浮游植物对营养盐添加的响应

2002年9月,通过现场营养盐添加实验研究了长江口外海(E4测站)、东海陆架中部海区(E6测站)以及黄海冷水团(E2测站)分粒级叶绿素a对营养盐添加的响应.结果显示:E6测站加磷与加氮磷组均在120h出现了叶绿素峰值响应,表明9月该站同时受氮磷限制.E4测站加磷组在第1天培养结束时就出现了叶绿素响应,证实了磷限制的存在.E2测站由于培养时间所限,加氮与加磷组均未观测到叶绿素明显的峰值响应.不同海区浮游植物对响应时间不尽相同.营养盐的添加在一定程度上改变了浮游植物的粒级结构.     

东中国海环流对2008年浒苔事件的影响

以2008年浒苔暴发期间每隔5天的海表温度和风场做强迫场,利用POM模型模拟得到2008年黄海浒苔事件期间的环流场.模拟的夏季黄海近岸表层流向北流动,流速较大;山东半岛南岸表层流向东北流动,流速较小.模拟结果显示,表层流场主要受到风向的影响.在夏季,黄海近岸表层流为向北然后转为向东北流动,形成顺时针旋转的环流.而环流产...     

东海南部暗鳍兔头鲀渔场环境因子初探

根据舟山海洋渔业公司近3年在东海南部暗鳍兔头鲀钓作业记载的日志和生产统计资料,初步分析了东海南部暗鳍兔头鲀渔场的环境因子,结果表明:暗鳍兔头鲀渔场的变动和渔获量与水温环境因子的关系较为密切.当水温在17～23℃时,暗鳍兔头鲀渔获量随着温度的升高大致增加;当水温高于23℃时,暗鳍兔头鲀渔获量随着温度的升高反而降低;黑潮、台湾暖流、冷水团等海流的变化影响着暗鳍兔头鲀渔场范围大小及其移动,近3年渔场基本稳定在26°0'～28°30'N,122°30'～126°00'E的海域;浮游生物的分布与垂直移动影响暗鳍兔头鲀栖息集群及鲀钓渔法,暗鳍兔头鲀作业渔场的浮游生物量为25~50 mg/m3.     

东海区海洋渔业资源近况浅析

根据2002～2004年东海区渔业资源监测调查资料、主要捕捞鱼种的生物学资料和中国渔业统计年鉴,对东海区近3 a季节间的资源密度、渔业生物学性状以及历年来的渔获群落结构组成、单位捕捞力量渔获量动态比较,分析东海区海洋渔业资源近况.结果表明:虽然近几年东海区海洋渔业捕捞产量维持在历史高水平,但主要是依赖于超高的捕捞力量、实施伏季休渔制度使群体资源得到暂时的养护等措施.主要经济鱼种的亲鱼量年间变化不大且处于相对缺乏的状态,渔获物小型化、利用资源主体以当龄鱼为主、单位捕捞力量渔获量下降等过度捕捞现象十分明显,资源基础相当脆弱,渔业资源衰退之势仍在加剧.秋季调查资源密度的年间波动取决于补充量水平,其水平的高低与环境因子密切相关.     

东海龙头鱼矢耳石形态特征研究

以2011年9-11月和2012年3-5月在舟山渔场捕获的496尾龙头鱼为样本,采用主成分分析、回归分析等方法对龙头鱼矢耳石形态特征进行了研究。结果显示,龙头鱼矢耳石呈不规则卵圆形,其基叶较长,翼叶不发达;后端具波纹状叶形晶状突,无后基叶和侧基叶。龙头鱼矢耳石形态指标AD(L)、CE(H)、OA(L1)、OD(L3)、AH(b1)、BG(b2)、AB(c1)和AG(c2)可代表龙头鱼矢耳石主要形态特征。8个指标均与体长及纯重呈显著正相关,其中L与体长及纯重相关性最强。龙头鱼矢耳石各指标值对长轴长的比值与其体长均不存在显著相关性,其耳石形态在生长过程中较为稳定。     

黄东海多毛类动物种类组成与优势种分析

【目的】探明黄东海区域多毛类Polychaeta物种组成状况。【方法】用0.1 m2 Gray-O’Hara箱式采泥器重复采样2次,对获得的多毛类样品进行准确的分类鉴定,采用优势度计算公式:Y=(ni/N)fi统计得出优势种并分析其空间分布状况。【结果】本次调查黄东海共鉴定出多毛类32个科90种,优势种为背蚓虫Notomastus latericeus Sars,1857和掌鳃索沙蚕Ninoe palmata Moore,1903,其分布没有表现出明显的规律性。【结论】黄东海多毛类种类丰富,优势种随时间变化而改变,而分类学研究应引起重视。     

东海赤潮生物具齿原甲藻及其特征

2000年至今连续三年的5月在东海的舟山海域发生大规模红褐色具齿原甲藻赤潮。在赤潮监测中对该种的形态及习性作了观察研究，结果表明：本种分布于我国东南沿海，主要分布于盐度较高的水域，5月份是繁殖盛期易发生赤潮，在河口低盐水域和高温季节不易发生赤潮，具齿原甲藻赤潮在近几年频繁发生与东海沿岸富营养化加剧有关。具齿原甲藻具有昼夜垂直移动特性，使得它们在获得光能、营养盐方面更具优势，在低磷环境中具有较强的种间竞争能力。对于大规模赤潮发生的原因、富营养化的贡献、种间竞争在赤潮发生过程中的作用等问题有待于进一步深入研究。     

东海黄海渤海8个主要分潮的数值模拟

应用球面坐标系下ECOM数值模式,数值模拟了东海黄海渤海的8个主要分潮M₂、S₂、N₂、K₂、K₁、O₁、P₁和Q₁.采用高分辨率网格,计算区域包括东海黄海渤海、东海陆架坡和琉球以东西北太平洋,考虑实际水深和岸线.开边界条件由全球大洋潮汐模式计算的调和常数给出.较成功地模拟出了8个分潮的传播特征,再现了计算区域内半日分潮的5个无潮点和2个蜕化的半个无潮点、全日分潮的3个无潮点.与65个潮位站的观测资料比较,模式计算的M₂、S₂、K1和O₁分潮振幅和位相的均方差分别为7.85 cm和6.81°,5.04cm和8.14°,3.82cm和13.04°,4.34cm和9.33°.与17个潮位站的观测资料比较,N₂、K₂、P₁和Q₁分潮振幅和位相的均方差分别为3.64cm和7.89°,8.47cm和10.51°,1.76cm和7.56°,1.50cm和26.34°.模式模拟的结果可为河口海岸小区域模式提供较为可靠的外海开边界潮汐调和常数资料.     

Carbon isotopic record of foraminifers in surface sediments from the South China Sea and its significance

Since the 1990s, the papers and data involved withthe South China Sea (SCS) have been emerging in largenumbers in the world as people pay more attention to thepaleoceanography of the SCS. There have been more than100 cores mentioned in papers containing p…     

基于耦合气候系统模式的中全新世黄、东海海表通量分析

对中全新世(6,ka时期)海洋和气候的研究可加深人们对现阶段气候变化和海洋环境的认识,为预测未来海洋与气候环境变化提供一个重要参照.文章分析一个耦合气候系统模式FGOALS-s2.0的模式结果,首先对其工业革命前(0,ka时期)东亚地区夏季降水及冬、夏季10,m风场的模拟结果进行评估,然后进一步对中全新世和工业革命前黄、东海海表大气强迫的季节变化进行了对比.结果显示:模式模拟出0,ka时期东亚夏季降水从东南洋面至西北内陆减少的空间分布特点,冬、夏季10,m风场亦与观测大体一致;6,ka时期夏季,黄、东海风速较0,ka时期增大约0.8,m/s,16%左右;黄海风应力旋度值为正,东海为负,与0,ka时期相比旋度绝对值均增大;同时,两海区接收的太阳短波辐射较0,ka时期均增加,短波辐射的差异是中全新世夏季黄、东海海表的净热吸收增加的主要因子.6,ka时期冬季,黄、东海北风加强,东海增加量在0.5~1.0,m/s,幅度约为10%,较黄海更为明显;两海区在冬季的净热释放也较0,ka时期增大,东海释放更甚;冬季黄、东海风应力旋度较0,ka时期则无太大差别.研究表明,由于6,ka时期太阳辐射季节循环的改变,造成了黄、东海夏季风增强,海表净热通量也发生相应变化,该时期大气强迫场的变化可能会使黄、东海表层水温分布趋势发生较大改变,进而影响陆架环流格局.