Fluxes of selected trace metals from the Seine estuary to the eastern English Channel during the period August 1994 to July 1995     

Jean-Franois Chiffoleau  Dominique Auger  Emmanuelle Chartier 《Continental Shelf Research》1999,19(15-16)

Two sampling cruises conducted in the Seine estuary (France) under low-water and flood conditions produced high resolution profiles for dissolved cadmium, lead, copper, zinc and nickel concentrations versus salinity. The distribution of dissolved trace metals differed depending on hydrologic conditions, partly because of the dilution of upstream inputs during flood periods. Daily fluxes of these dissolved trace metals were estimated for the two sampling periods (September 1994 and February 1995) by extrapolating the dilution lines observed in higher salinity waters to salinity=0 and then multiplying the effective freshwater concentrations thus obtained by the corresponding freshwater flow. Several procedures were subsequently applied to deduce each daily flux for the year studied from data for these two periods. A consensus was found among these procedures, allowing the determination of net fluxes of dissolved trace metals with a precision of 20–35%. The net fluxes thus estimated were 4 T yr⁻¹ for Cd, 4 T yr⁻¹ for Pb, 40 T yr⁻¹ for Cu, 130 T yr⁻¹ for Zn and 50 T yr⁻¹ for Ni.  相似文献   

Plankton distributions in relation to physical oceanographic features on the southern Malin Shelf, August 1996     

Gowen  R. J.; Raine  R.; Dickey-Collas  M.; White  M. 《ICES Journal of Marine Science》1998,55(6):1095-1111

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南黄海中部隆起中-古生代地层发育新认识——基于大陆架科学钻探CSDP-02井钻探成果   总被引：2，自引：0，他引：2       下载免费PDF全文

张晓华  张训华  吴志强  郭兴伟  肖国林 《地球物理学报》2018,61(6):2369-2379

南黄海中部隆起海相地层埋藏浅,是南黄海盆地油气勘探的重点,但由于缺乏钻井资料约束,中部隆起中-古生界的地层属性一直存在争议.大陆架科学钻探CSDP-02井是南黄海中部隆起第一口钻井,也是南黄海盆地钻遇地层最深的一口全取心井.本文在分析大陆架科学钻探CSDP-02井的岩心、测井和相应多道地震资料基础上,明确了中部隆起中-古生界的地层属性：在新近系充填沉积之下,依次发育三叠系下统青龙组下段、二叠系上统大隆组、龙潭组,二叠系下统孤峰组、栖霞组,石炭系船山组、黄龙组、和州组和高骊山组,泥盆系五通群和志留系高家边组、奥陶系.结合地球物理测井曲线分析与区域地质认识,确定了地震反射界面T2、T8、T9、T10、T11的反射特征与对应的地质界面.中部隆起地层分布特征整体受南黄海构造运动的影响,早古生代地层平缓,断裂不发育,加里东运动造成志留系上统及中下泥盆统沉积缺失,石炭系-二叠系在中部隆起广泛发育,厚度大,二叠系最大沉积厚度约1900 m,中生界残留地层分布局限,主要保存下三叠系,地层厚度变化范围较大.  相似文献   

新一代冰流模式乌阿及其在南极埃默里冰架的应用   总被引：1，自引：1，他引：0  

李腾  陈卓奇  李慧林  程晓  韦屹  刘岩 《冰川冻土》2020,42(1):254-264

南极冰盖不仅是全球环境变化的指示器, 其消融所产生成的淡水输入也是未来海平面上升的主要不确定性来源。数值模式是诊断冰流动力机制、 评估冰盖物质损耗的重要手段。本文首先介绍了乌阿（冰岛语úa或英语Ua）冰流模式的基本原理, 并利用该模式模拟东南极埃默里冰架的动态变化。乌阿冰流模式基于质量和动量守恒方程的垂直积分, 在自适应不规则三角网格上求解微分方程, 仅用少数参数规则即可构造适应冰流动力特征的网格结构, 有效缩减运算时间。采用当前主流的模式边界数据集, 针对埃默里冰架设计了两个试验。试验一为反演试验, 试验中模式的代价函数在100次迭代后下降三个数量级, 表明模拟的流速与遥感观测吻合（RMSE = 13.35 m·a^-1）, 但高频细节仍有待提高; 试验二为预测试验, 测试了模拟冰厚变化率的不确定性, 以自由漂移量接近零为标准选出一组最优模型参数, 最后假设埃默里冰架解体情景开展模拟, 结果表明冰架解体会导致海平面上升（45.36 ± 0.08） mm。随着资料更新迭代, 基于最新发布的南极底部地形数据模拟效果是否提升还有待未来检验。  相似文献   

华南东部陆缘新生代隆升历史及其动力学机制     

王新毓  索艳慧  李三忠  曹现志  李玺瑶  周洁  王鹏程  金宠 《岩石学报》2020,36(6):1803-1820

华南陆缘在新生代期间经历了千米量级的上覆盖层剥蚀和山脉隆升;同时,其东侧的东海陆架盆地经历多次构造应力场的反转并发育多期反转构造。东海陆架盆地内的构造反转与华南陆缘隆升的发生时间和触发机制是否一致有待研究。为此,本文对浙江地区的岩石样品进行磷灰石裂变径迹测试和热演化史反演分析其隆升历史,并通过地震剖面分析东海陆架盆地的反转时间及其反转所导致的地层剥蚀量;最后,将二者进行对比分析并研究其动力学机制。结果发现,华南东部陆缘地区至少存在晚始新世(34. 5～33. 5Ma)、中中新世(16～11. 5Ma)、上新世以来(5～0Ma)三期明显的快速隆升事件,三期隆升导致的地层剥蚀量分别为227m、593m和865m;东海陆架盆地经历了古新世末-始新世初(～56Ma)、始新世末-渐新世初(～32Ma)和晚中新世(～10Ma)三期构造反转,三期反转导致的局部地层最大剥蚀量分别可达1200m、1300m和2000m。在时间上,东海陆架盆地的始新世末-渐新世初(～32Ma)和晚中新世(～10Ma)的构造反转分别滞后于浙江的晚始新世(34. 5～33. 5Ma)和中中新世(16～11. 5Ma)的隆升时间,说明这两期挤压-剥蚀事件分别具有自西向东的迁移性,即印度-欧亚板块碰撞的远程效应可能是导致该迁移特征的原因;在强度上,东海陆架盆地的反转剥蚀量大于浙江境内的地层隆升量、挤压强度东强西弱,中新世晚期菲律宾海板块向西俯冲导致冲绳海槽弧后伸展产生向西的挤压力、这种挤压应力向陆内传递且强度变弱可能是导致该特征的原因。  相似文献   

The Australian continental shelf: Has Australia's high-latitude diplomacy paid off?’     

Julia Jabour 《Marine Policy》2009

The Commission on the Limits of the Continental Shelf has granted Australia extended continental shelf areas around two of its sub-Antarctic island groups, and these extend into the Antarctic Treaty area. The overlap potentially raises conflict between Australian and Antarctic interests. Australia's submission included and expressly excluded Antarctic data and its high-latitude diplomacy paid off, but its next steps will be crucial to gaining acceptance by other Antarctic Treaty parties. It is likely that any resource exploitation will stop at the fence (60° South) during the life of the Treaty.  相似文献   

Observational and numerical modeling methods for quantifying coastal ocean turbulence and mixing   总被引：6，自引：0，他引：6  

Hans Burchard  Peter D. Craig  Hans van Haren  H.E. Markus Meier  Hartmut Prandke  Eric D. Skyllingstad  David J.S. Welsh  Hemantha W. Wijesekera 《Progress in Oceanography》2008,76(4):399-442

In this review paper, state-of-the-art observational and numerical modeling methods for small scale turbulence and mixing with applications to coastal oceans are presented in one context. Unresolved dynamics and remaining problems of field observations and numerical simulations are reviewed on the basis of the approach that modern process-oriented studies should be based on both observations and models. First of all, the basic dynamics of surface and bottom boundary layers as well as intermediate stratified regimes including the interaction of turbulence and internal waves are briefly discussed. Then, an overview is given on just established or recently emerging mechanical, acoustic and optical observational techniques. Microstructure shear probes although developed already in the 1970s have only recently become reliable commercial products. Specifically under surface waves turbulence measurements are difficult due to the necessary decomposition of waves and turbulence. The methods to apply Acoustic Doppler Current Profilers (ADCPs) for estimations of Reynolds stresses, turbulence kinetic energy and dissipation rates are under further development. Finally, applications of well-established turbulence resolving particle image velocimetry (PIV) to the dynamics of the bottom boundary layer are presented. As counterpart to the field methods the state-of-the-art in numerical modeling in coastal seas is presented. This includes the application of the Large Eddy Simulation (LES) method to shallow water Langmuir Circulation (LC) and to stratified flow over a topographic obstacle. Furthermore, statistical turbulence closure methods as well as empirical turbulence parameterizations and their applicability to coastal ocean turbulence and mixing are discussed. Specific problems related to the combined wave-current bottom boundary layer are discussed. Finally, two coastal modeling sensitivity studies are presented as applications, a two-dimensional study of upwelling and downwelling and a three-dimensional study for a marginal sea scenario (Baltic Sea). It is concluded that the discussed methods need further refinements specifically to account for the complex dynamics associated with the presence of surface and internal waves.  相似文献   

Origin and fate of particulate organic matter in the southern Beaufort Sea – Amundsen Gulf region,Canadian Arctic     

Cédric Magen  Gwénaëlle Chaillou  Sean A. Crowe  Alfonso Mucci  Bjørn Sundby  Aiguo Gao  Ryosuke Makabe  Hiroshi Sasaki 《Estuarine, Coastal and Shelf Science》2010

To establish the relative importance of terrigenous and marine organic matter in the southern Beaufort Sea, we measured the concentrations and the stable isotopic compositions of organic carbon and total nitrogen in sediments and in settling particles intercepted by sediment traps. The organic carbon content of surface sediment in the Chukchi and southern Beaufort Seas ranged from 0.6 to 1.6% dry wt., without a clear geographical pattern. The C_ORG:N_TOT ratio ranged from 7.0 to 10.4 and did not vary significantly downcore at any one station. Values of δ¹³C_ORG and δ¹⁵N_TOT in the sediment samples were strongly correlated, with the highest values, indicative of a more marine contribution, in the Amundsen Gulf. In contrast, the organic matter content, elemental (C_ORG:N_TOT ratio) and isotopic (δ¹³C_ORG and δ¹⁵N_TOT) composition of the settling particles was different from and much more variable than in the bottom sediments. The isotopic signature of organic matter in the Beaufort Sea is well constrained by three distinct end-members: a labile marine component produced in situ by planktonic organisms, a refractory marine component, the end product of respiration and diagenesis, and a refractory terrigenous component. A three-component mixing model explains the scatter observed in the stable isotope signatures of the sediment trap samples and accommodates an apparent two-component mixing model of the organic matter in sediments. The suspended matter in the water column contains organic matter varying from essentially labile and marine to mostly refractory and terrigenous. As it settles through the water column, the labile marine organic matter is degraded, and its original stable isotope signature changes towards the signature of the marine refractory component. This process continues in the bottom sediment with the result that the sedimentary organic matter becomes dominated by the refractory terrigenous and marine components.  相似文献