近190ka BP以来菲律宾海黑潮源区的碳酸盐旋回及其控制因素   总被引：2，自引：0，他引：2  

赵京涛  常凤鸣  李铁刚  南青云  李青 《岩石学报》2008,24(6):1401-1410

对取自西菲律宾海黑潮源区的Ph05-5和WF3岩芯进行了CaCO3和钙质超微化石研究.在利用氧同位素曲线对比和AMS14C数据进行地层划分的基础上,结合钙质超微化石的碳酸盐溶解指数和初级生产力指标,分析了晚第四纪黑潮源区碳酸盐旋回特征及其控制因素.约190ka BP以来CaCO3含量整体上都表现为冰期高、间冰期低的"太平洋型"旋回特征,但菲律宾以东海区在末次冰期(MIS 4到MIS 2期)内部又显示出间冰段含量高、冰段含量低的"大西洋型"旋回特征.碳酸盐旋回的控制因素在黑潮源区内部也有明显的差异,菲律宾以东海区以碳酸盐溶解作用为主,初级生产力起次要作用;而台湾东南部海区的主要因素则是初级生产力变化引起的钙质生物输入量的波动.菲律宾以东海区末次冰期内部表现出的"大西洋型"旋回特征则是溶解作用和初级生产力共同影响的结果.  相似文献   

北大别白垩纪镁铁－超镁铁岩的铂族元素地球化学研究   总被引：2，自引：0，他引：2       下载免费PDF全文

刘 庆侯泉林  周新华谢烈文 《中国地质》2008,35(5):859-868

采用镍锍火试金法结合ICP-MS分析了12个北大别白垩纪镁铁-超镁铁岩样品的Ir,Ru,Rh,Pt和Pd的含量,结果显示铂族元素（PGE）的含量较低,原始地幔标准化后的PGE分布模式呈正斜率型,PPGE相对原始地幔略微亏损,而IPGE强烈亏损,Pd/Ir值远高于相应的地幔比值。这些镁铁-超镁铁岩中PGE的强烈分异是地幔低程度的部分熔融过程中,PPGE主要受硫化物控制,而Ir则存在于非硫化物相如尖晶石,可能还有合金之中造成的。同时,铂族元素的分布特征表明这些镁铁-超镁铁岩是岩浆结晶分异的产物。  相似文献   

Diel Patterns in Chlorophyll <Emphasis Type="Italic">a</Emphasis> Specific Absorption Coefficient and Absorption Efficiency Factor of Picoplankton     

Nobuaki?OhiEmail author  Hiroaki?Saito  Satoru?Taguchi 《Journal of Oceanography》2005,61(3):379-388

Diel patterns in the chlorophyll a specific absorption coefficient of surface picoplankton, a*_pico (γ) (m²·[mg chlorophyll a]⁻¹), were studied at 7 stations under daily cycle of in situ light condition in the western subarctic Pacific and Japan Sea. All the data were normalized by dividing the anomaly with daily averaged a*_pico (γ). Opposite diel patterns were observed for the normalized a*_pico (443) and a*_pico (675) with maximum toward dawn or dusk and minimum toward midday at 4 stations under low-irradiance (LI) conditions and vice versa at 3 stations under high-irradiance (HI) conditions. The absorption efficiency factors at red absorption peak, Q _a (675), were determined by reconstruction with intracellular chlorophyll a concentration and cell diameter. The normalized Q _a (675) also showed diel pattern with maximum toward midday and minimum toward dawn or dusk under LI. The diel pattern in a*_pico (675) and Q _a (675) were primarily caused by changes in intracellular chlorophyll a concentration due to photoadaptation under LI. The diel pattern in a*_pico (443) was influenced by pigmentation, as recognized by blue to red ratio [a*_pico (443)/a*_pico (675)] under HI. This study proposed that the opposite diel pattern in a*_pico (γ) might occur for a wide range of algal species. The results presented here have important consequences for the interpretation of diel variations in optical properties observed in the open ocean.  相似文献   

不同风区海面雷达后向散射的极化特征对比分析     

董庆  郭华东  王长林 《海洋通报》2000,19(2):1-7

通过对海南省南保港附近海面ＳＩＲ－Ｃ／Ｘ－ＳＡＲ全极化数据的定量研究,对比研究了该海面不同风区海面的全极化信息特征,定量分析了海面散射的极化信息和极化状态的空间结构情况：用散射矩阵的迹解释了不同海区的散射强度对应关系：对比海面散射极化响应可以确定不同成长类型的粗糙海面类型;用极化响应图的对称特点界定“长尺度”和“短尺度”海面;建立全极化海面散射模型。讨论了海面电磁散射的贡献与雷达系统参数之间的定量  相似文献   

海洋石油管道单点提升分析   总被引：3，自引：0，他引：3  

邢静忠  柳春图等 《海洋工程》2002,20(3):29-33

基于管道微单元体平衡建立了海管单点提升的非线性力学模型的控制微分方程组 ,使用变弧长的无量纲代换将动边界问题化为固定边界的两点边值问题 ,利用Maple环境下编制的两点边值问题的打靶法程序得到了该问题在各个提升阶段的数值解答和在单点提升过程中管道的极限弯矩约为 0 .71q1 3(EI) 2 3。  相似文献   

CO<Subscript>2</Subscript> Flux Measurements over the Sea Surface by Eddy Correlation and Aerodynamic Techniques     

Toru?Iwata  Keiko?Yoshikawa  Katsutoshi?Nishimura  Yoshihisa?Higuchi  Takao?Yamashita  Shigeru?Kato  Eiji?OhtakiEmail author 《Journal of Oceanography》2004,60(6):995-1000

The measurements of the vertical transport of CO₂ were carried out over the Sea of Japan using the specially designed pier of Kyoto University on September 20 to 22, 2000. CO₂ fluxes were measured by the eddy correlation and aerodynamic techniques. Both techniques showed comparable CO₂ fluxes during sea breeze conditions: −0.001 to −0.08 mg m⁻²s⁻¹ with the mean of −0.05 mg m⁻²s⁻¹. This means that the measuring site satisfies the fetch requirement for meteorological observations under sea breeze conditions. Moreover, the eddy diffusivity coefficient used in the aerodynamic technique is found to be consistent with the coefficient used in the eddy correlation technique. The present result leads us to conclude that the aerodynamic technique may be applicable to underway CO₂ flux measurements over the ocean and may be used in place of the bulk technique. The important point is the need to maintain a measuring accuracy of CO₂ concentration difference of the order of 0.1 ppmv on the research vessels or the buoys.  相似文献   

Long-Term Investigation of Spatio-Temporal Variations in Faunal Composition and Species Richness of Megabenthos in Ise Bay,Central Japan     

Monthon?Ganmanee  Teruyoshi?Narita  Hideo?SekiguchiEmail author 《Journal of Oceanography》2004,60(6):1071-1083

Based on our long-term data from megabenthos sampling from 1993 to 2002 in Ise Bay, central Japan, we examined spatio-temporal variations in taxon composition, species richness and its distribution of megabenthos in the bay in relation to the occurrence of the oxygen-poor water (i.e. oxygen content less than 3 ppm) in bottom waters of the bay. A total of 261 species were identified including 6 cnidarians, 1 tentaculate, 5 annelids, 71 molluscs, 72 crustaceans, 16 echinoderms, 12 urochordates and 78 pisces. Of the most abundant 10 megabenthos species, the following 4 species of echinoderms made up more than the half of megabenthos biomass: Luidia quinaria, Echinocardium cordatum, Asterias amurensis and Astropecten scoparius. Species richness of megabenthos varied significantly between seasons and among stations. The severity and period of occurrence of the oxygen-poor water developing every summer play an important role in determining spatial distributions of species richness in the bay.  相似文献   

合浦珠母贝26S蛋白酶体S4,S7亚基基因片段的分离与分析     

姜铁民  张勇  黄洁  谢莉萍  吴移谋  张荣庆 《海洋科学》2003,27(4):28-34

26S蛋白酶体是真核生物中一种具有ATP依赖性的蛋白酶复合体,主要通过泛肽途径选择性降解细胞内与代谢调控、细胞周期有关的功能蛋白及异常蛋白,参与多种细胞活动的调控过程。26S蛋白酶体由具有催化活性的20S亚复合体和一个具有调节作用的19S亚复合体组成,其中19S亚复合体中的ATP酶亚基是调节26S蛋白酶体活性的重要组件。本通过简并引物PCR手段,从软体动物合浦珠母贝(Pinctada fucata)中扩增到参与构成19S亚复合体的S4和S7(MSS1)两个亚基的基因片段。这两个基因片段所编码的ATP酶组件包含有Gx4GKT,DEID,SAT和H／QRxGRxxR等26S蛋白酶体ATP酶亚基的共同功能基序。这是首次在软体动物中报道26S蛋白酶体的ATP酶亚基基因序列,为研究软体动物中26S蛋白酶体的结构与功能奠定了分子基础。  相似文献   

Competition within the marine microalgae over the polar dark period in the Greenland Sea of high Arctic   总被引：2，自引：0，他引：2  

Zhang Qing  Rolf Gradinger  Zhou Qingsong 《海洋学报(英文版)》2003,22(2):233-242

Abstract-With the onset of winter, polar marine microalgae would have faced total darkness for aperiod of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected fordark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Po-larstern in October 1995. After a dark period of 161 days, species dominance in the algal assemblagehave changed from initially pennate diatoms to small phytoflagellates (<20μm). Over the entire darkperiod, the mean algal growth rate was-0.01 d~(-1). Nearly all diatom species had negative growthrates, while phytoflagellate abundance increased. Resting spore formation during the dark period was ob-served in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We as-sume that facultative heterotrophy and energy storage are the main processes enabling survival during thedark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth withindays. Phytoffa  相似文献   

远区台风“三巴”对长江口波浪动力场的作用机制     

任剑波  何青  沈健  徐凡  郭磊城  谢卫明  朱磊 《海洋科学》2020,44(5):12-23

针对远区台风对河口波浪动力场的影响问题,利用第三代波浪模式SWAN计算了远区台风"三巴"期间长江口波浪动力场分布,分析了陆架至河口区的波浪能量耗散和波致泥沙侵蚀的时空分布,发现波浪由外海向近岸传播过程中,波-波相互作用导致能量由高频向低频转换,周期和波长逐渐增大,近底层轨道流速增大,能量密度增高;阐明白帽破碎是维持深水区波浪能量平衡和限制波高成长的主要机制,底摩擦耗能和水深诱导的破碎耗能是长江口横沙东滩和崇明东滩邻近海域波高衰减的主要原因;提出波浪产生的底部切应力与相对水深有关,当波浪传播到浅水区时,波长和周期越大,波浪切应力越大。研究揭示了与河口相距数百公里的远区台风能够对长江口波浪动力场产生明显影响,河口水下三角洲前缘是最容易受到波浪侵蚀的区域,研究成果弥补了目前关于陆架远区台风对河口波浪动力场影响研究的不足,对深化认识远区台风对长江口动力环境、地貌演变、航运安全和滩涂保护等有重要科学意义。  相似文献