Latitudinal change in benthic foraminiferal fauna by ITCZ movement along the ~131°W transect in the equatorial Pacific Ocean
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- 作者：Hiroyuki Takata ; Chan Min Yoo ; Hyung Jeek Kim ; Boo-Keun Khim
- 关键词：benthic foraminifera ; ITCZ ; productivity ; Late Quaternary ; equatorial Pacific
- 刊名：Ocean Science Journal
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：51
- 期：4
- 页码：655-663
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Oceanography; Marine & Freshwater Sciences; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution;
- 出版者：Korea Ocean Research and Development Institute and The Korean Society of Oceanography
- ISSN：2005-7172
- 卷排序：51
文摘
Modern and fossil benthic foraminifera were examined from nine surface sediments and two piston cores along the ~131°W transect in the equatorial Pacific Ocean. This study was conducted to clarify the biotic response of abyssal benthic foraminifera during the last 220 ka to changes in the seasonal extent of the Intertropical Convergence Zone (ITCZ). The abundance of modern benthic foraminifera was high at stations between the equator and 6°N, whereas it was low at stations north of 6°N, which is generally consistent with the latitudinal CaCO3 distribution of surface sediments. The northward increase of Epistominella exigua from the equator to ~6°N is similar to the seasonal variations in chlorophyll-a concentrations in the surface water and ITCZ position along ~131°W. This species was more common at core PC5103 (~6°N) than at core PC5101 (~2°N) after ~130 ka, when the Shannon-Wiener diversity (H’) between the two cores started to diverge. Hence, the presentday latitudinal difference in benthic foraminifera (E. exigua and species diversity) between ~2°N and ~6°N along ~131°W has been generally established since ~130 ka. According to the modern relationship between the seasonality of primary production and seasonal ITCZ variations in the northern margin of the ITCZ, the latitudinal divergence of benthic foraminiferal fauna between ~2°N and ~6°N since ~130 ka appear to have been induced by more distinct variations in the seasonal movement of ITCZ.