Silicon limitation on primary production and its destiny in Jiaozhou Bay, China——Ⅳ：Study on cross-bay transect from estuary to ocean

The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m³/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05–0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55 (mgC/m²·d)/(m³/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m²·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs. 1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth. This study was funded by NSFC (No. 40036010), and the Director's Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.     

河南桐柏老湾花岗岩体锆石SHRIMP U-Pb年龄及其地质意义

通过对河南桐柏老湾花岗岩体开展锆石SHRIMP U-Pb测年,获得了一个高精度的U-Pb年龄(132.5±2.4)Ma,比较可靠地限定了老湾花岗岩体的形成时代属于燕山中期,而不是前人所认为的燕山晚期.结合区域构造-岩浆活动时间,认为在燕山中期,桐柏及其邻区存在次比较重要的构造-岩浆事件,老湾花岗岩体是这次构造-岩浆活动事件的产物.     

从沉积物中重矿物动力分区论钦州湾泥沙来源及运移趋势

钦州湾沉积物中重矿物组合大体上划分为四个动力分区：内湾茅尾海重矿物区即钛铁矿－电气石－锆石－赤铁矿组合区，湾颈－外湾重矿物区即钛铁矿－赤铁矿－矿石－电气石组合区，外湾东部重矿物区即电气石－锆石－钛铁矿组合区，外湾西南部重矿物区即电气石－钛铁矿－锆石组合区。在重矿物动力分区的基础上，探讨钦州湾泥沙来源及其运移趋势。     

珠江三角洲晚第四纪沉积特征

本文主要研究珠江三角洲的第四纪地层;晚更新世玉木亚间冰期、全新世中期(大西洋期)海侵阶段的地貌景观及珠江三角洲晚第四纪以来的沉积形成过程。     

薛家岛湾沉积动力学特征及海港开发研究

于１９９０年秋对胶州湾内的薛家岛湾进行海洋水动力条件及积动力学特征,泥沙运动规律研究,为开发建设港口提供科学依据。结果表明,湾内深大于１ｍ的海底泥沙发生“全面移动”的时间,一年内仅有１－２ｄ,其余处于稳定状态或“表面移动”状态。湾内泥沙来源很少,预计建港后,港池和航道年平均回淤量分别小于１６ｃｍ,１０ｃｍ对于开发中小型港口十分有利。     

湄州湾沉积物地球化学特征

根据湄州湾表层沉积物70个样品18个化学成分的分析结果,得出:本海区沉积物属于海相陆源物,其中细颗粒主要来自台湾海峡,粗颗粒来自当地陆域;化学成分含量按聚类分析,可归为三组:粘土矿物组、碳酸盐组和分散组,微量元素Zn,Cr,Be,Cu和Sr的含量与地壳及台湾海峡相似,但低于胶州湾,说明该海区污染很少。     

普里兹湾陆缘水边界的变化

利用１９９８年１１月－１９９９年２月中国第１５次南极考察资料,讨论了普里兹湾附近陆缘水边界（ＣＷＢ）两侧的水团分布,以及ＣＷＢ的中心位置、锋面宽度、锋面强度、锋面的垂直深度和垂直厚度等物理特征的空间变化。并与１９９２年１２月－１９９３年２月中国第９次南极考察资料进行了比较,说明了ＣＷＢ的时间２变化。同时,还进一步分析了ＣＷＢ两侧海水运动的各向异性,以及动力高度场的形势,指出了动力高度槽,ＣＷＢ锋面     

莱州湾海洋农牧场建设的可能性

本文分析了莱州湾的渔业生态环境、渔业资源及其开发现状，提出了在莱州湾建设海洋农牧场的设想。进行海洋农牧场建设，海洋渔业生态环境首先需要恢复，还要对海区目前的渔业生产结构做适当调整，建立集约化养殖系统及其配套工程，是近海渔业生产摆脱狩猎式传统渔业走向养牧式渔业的必然途径。