Analysis for marine environmental changes during the past five million years, based on the benthic foraminiferal evidences
| Project/Area Number |
09640557
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Stratigraphy/Paleontology
|
|---|
| Research Institution | Kochi University |
|---|
Principal Investigator |
YASUDA Hisato Kochi University, Faculty of Sciences, Associate Professor, 理学部, 助教授 (90175646)
|
|---|
| Project Period (FY) |
1997 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Keywords | benthic foraminifera / marine environment / Earth environment / historical changes in ocean circulation / cycles / Milankovitch Cycles / 海洋環境変動 / 海洋生物生産 / milankovitch cycle / タスマン海台 / 周期性 / 西赤道大西洋 / 深層水循環 / 表層生産性 / 北大西洋深層水 / 南極底層水 |
|---|
| Research Abstract |
The accumulation rates of benthic foraminifers in two piston cores from the Tasman increased five- to eight-fold during glacial intervals of the past 500,000 years, indicating drastic increases of biological productivity of the overlying waters. During interglacial periods the benthic faunas are composed mainly of infaunal species that indicate relatively low and constant influx of organic matter. During glacial periods, the benthic foraminiferal faunas are characterized by drastic increases of the so-cal led phytodetritus feeding species Alabaminella weddellensis and Epistominella exigua. The sharp foraminiferal abundance increases indicate a northward displacement of the high-productivity region of the Polar Frontal Zone during glacial intervals. The preponderance of phytodetritus feeders documents that the high primary productivity was strongly pulsed, probably in the form of spring blooms that overwhelmed the grazing capacity of planktonic heterotroph consumers.
|
Report
(4 results)
Research Products
(6 results)
