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Changes in marine-plankton diatom assemblages due to formation and development of Circum-Antarctic Current

环南极流形成和发展导致海洋浮游生物硅藻组合的变化

基本信息

批准号：
09839042
负责人：
TANIMURA Yoshihiro
金额：
$ 2.18万
依托单位：
National Science Museum
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09839042/
关键词：
marine plankton Circum-Antarctic Current diatoms 南極還流

项目摘要

A time series of 65 sediment trap samples deployed in the western North Pacific Ocean, representing 48-month changes in diatom flora, seven DSDP (Deep Sea Drilling Program) cores from the Ocean, and 20 sea water and sea-ice samples from Lutzow-Holm Bay of Antarctica were analyzed.Temporal and spatial distribution of a single cosmopolitan diatom species, Thalassionema nitzschioides, and its varieties were found to be linked with the history of differentiation and distribution surface water masses due to changes in the ocean circulation system.In DSDP-ODP (Ocean Drilling Program) cores, T.nitzschioides is common in all late Paleogene to Quaternary sequences but not in cores from modern high-latitude Antarctic seas, over which Circum-Antarctic Current flows. Temporal variations of diatom abundance and species composition at Ocean Drilling Program Site 1095 cored on the continental rise along the Pacific side of Antarctic Peninsula were used to investigate the history of Polar Front migrations. The increases in abundance of T.nitzschioides at 5.7, 5.2-4.7 and 4.4-3.7 Ma, suggest a migration of Polar Front or Antarctic Convergence, a major boundary of plankton provinces in the modern Southern Ocean, to this site.These results suggest that temporal and spatial distribution of T.nitzschioides and its varieties is a new proxy for delineating the evolution of plankton provinces in relation to changes in distribution of surface water masses in the geologic past.

在北太平洋西部部署了65个沉积物捕集器样品的时间序列，代表硅藻植物群48个月的变化，7个DSDP通过对南极Lutzow-Holm湾20个海水和海冰样品的分析，研究了一种世界性硅藻Thalassionema nitzschioides的时空分布，在DSDP-ODP中，由于海洋环流系统的变化，表层水团的分异和分布历史与其变化有关（大洋钻探计划）岩心中，T.nitzschioides在所有古近纪晚期到第四纪层序中很常见，但在现代高纬度南极海的岩心中却不常见，环南极洋流流经的区域利用南极半岛太平洋侧大陆隆起沿着大洋钻探1095站位硅藻丰度和种类组成的时间变化研究了极锋迁移的历史。在5.7，5.2-4.7和4.4- 3.7Ma，菱形藻丰度的增加表明，现代南大洋浮游生物区的主要边界--极锋或南极辐合带发生了迁移，这些结果表明，Nitzschioides及其变种的时空分布是描述浮游生物省演变与变化关系的新指标在过去的地质时期地表水体的分布。