权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Calcareous nannoflora and carbonate flux variations associatd with the dynamic change of the Western Pacific Warm Pool

西太平洋暖池动态变化中的钙质纳米植物区系和碳酸盐通量变化

基本信息

批准号：
11304032
负责人：
OKADA Hisatake
金额：
$ 21.08万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11304032/
关键词：
western Pacific Warm Pool Calcareous nannoplankton Coccolith Carbonate Flux Watermass ENSO フラックス

项目摘要

We have studied the three dimensional distribution of calcareous nannoplankton in the Western equatorial Pacific and have identified, 1) the flora differs across the thermocline in the high-temperature water, warm eutrophic water and warm oligotrophic water regimes, but 2) no floral difference can be seen in the temperate mixed-water regime. By analyzing 485 tropical and subtropical Pacific surface-water samples including 351 samples collected by the Lamont-Doherty Earth Observatory, we have identified seven different floras correlating to different surface trophic levels. The distribution pattern of these floras clearly correspond to the longitudinal gradient in the surface nutrient level, and was the first observation of the longitudinal distribution in nannoplankton flora in a pelagic environment. We have also reported unusual concentration of very small placoliths in a tropical upwelling waters and have indicated paleoceanographic usefulness of these very small taxa.For the multi-year study of seasonal variations of calcareous nannoplankton in the tropical Pacific using the sediment-trap samples, we have obtained continuously the transition from La Nina to El Nino phases. Although the last batch of samples were just recovered and the analysis is continuing, we are now sure that the Molfino and Mclntyre (1991) Model that is widely used for paleoceanographic reconstructions does not work in the tropical Pacific where the nutricline is quite deep. A new methodology was proposed for a quantitative study of nannofossils in sediment samples, and by using this new technique we have analyzed several Quatemary cores for hgih-resolution paleoceanography.

本文对赤道西太平洋钙质超微浮游植物的三维分布进行了研究，结果表明：(1)在高温水、暖富营养化水和暖低营养化水条件下，温跃层的植物区系存在差异，而在温带混合水条件下，区系差异不明显。通过对拉蒙特-多尔蒂地球观测站采集的485个热带和亚热带太平洋表层水样(包括351个水样)的分析，我们确定了7个不同的植物区系，它们与不同的表层营养水平有关。这些植物区系的分布格局明显对应于表层营养层的纵向梯度，这是首次在远洋环境中观察到超微浮游植物区系的纵向分布。我们还报告了热带上升流水域中非常小的地块的异常集中，并指出了这些非常小的类群的古海洋学意义。为了利用沉积物捕获样本对热带太平洋钙质超微浮游植物的季节变化进行多年研究，我们连续获得了从拉尼娜到厄尔尼诺的过渡阶段。尽管最后一批样品刚刚被回收，分析仍在继续，但我们现在可以肯定的是，广泛用于古海洋学重建的Molfino和Mclntyre(1991)模型不适用于热带太平洋，那里的中线相当深。提出了一种定量研究沉积物样品中超微化石的新方法，并利用这一新技术分析了几个高分辨率古海洋学的第四纪岩心。