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Study on material circulation in the northwest Pacific Ocean based on sediment trap.

基于沉积物捕集的西北太平洋物质循环研究

基本信息

批准号：
02303007
负责人：
OBA Tadamichi
金额：
$ 7.36万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02303007/
关键词：
Sedement trap Flux Japan Trench Northwest Pacific Material circulation JGOFS 炭素循環

项目摘要

The oceanic trenches are the last unexplored region of the global environment. We have been continuing a time series of sediment trap experiments in the deepest part of the Japan Trench since August 1986. One trap was set 400 m above the bottom and other was set at the mid-depth of 4-5000 m. Two more traps were added at about 1000 m and 3500 m water depths since 1990. The following main results were obtained.1) Vertical flux of total mass and organic materials in the trench areas were relatively higher than those measured in other oceanic areas.2) A significant temporal variation of total particle flux was observed, but it is not simply related with the surface productivity.3) In general, the deeper trap collected more materilas than the shallow one, indicating transportation of resuspended matter from the trench slope.4) High fluxes of resuspended matter are suggested by the analysis of radio-isotopes, organic material composition, as well as microfossil tests such as coccolith and foraminifera.5) Planktonic tests such as diatom, radiolaria, coccolith, foraminifera, and palynomorph show distinct seasonal variations in their fluxes and species compositions. They are affected by the production rate in the surface layer, dissolution rate of the calcium carbonate, and changes of the water mass above the traps.6) Oxygen and carbon sotopic measurements of individual spciemens of foraminifera indicate that the isotopic compositions of the test are essentially controlled by the temperature and carbon isotope of the sea water in which the specimen grew.

海沟是全球环境中最后一个未被探索的区域。自1986年8月以来，我们一直在日本海沟最深处进行沉积物捕获实验的时间序列。一个圈闭设置在底部以上400 m处，另一个设置在4-5000 m的中深度处。自1990年以来，在约1000 m和3500 m水深处又增加了两个捕集器。主要结果如下：1）海沟区总物质和有机物的垂直通量相对较高; 2）总颗粒通量的时间变化显著，但并不与表层生产力简单相关; 3）总的来说，深陷阱比浅陷阱收集更多的物质，4）放射性同位素、有机物质成分分析以及微体化石测试（如颗石和有孔虫）表明存在高通量的再悬浮物质。5）浮游生物测试（如硅藻、放射虫、颗石、有孔虫、和孢粉型的通量和物种组成具有明显的季节变化。它们受表层生产率、碳酸钙溶解率和圈闭上方水体质量变化的影响。6）有孔虫个体的氧、碳同位素测定表明，试验的同位素组成基本上受样品生长的海水的温度和碳同位素控制。