Modern benthic foraminifera along a transect at 131W in the central equatorial Pacific Ocean and its application to MIS 8 paleoceaography

Abstract

Abyssal benthc foraminifera in the central equatorial Pacific Ocean seemed to respond to the fluctuations of Intertropical Convergence Zone (ITCZ), but knowledge on modern benthic foraminifera is still limited. We investigated modern benthic foraminifera from six surface sediments of KODOS05-02 cruise along a transect at 131W, focusing on correspondence to the ITCZ position. Nuttallides umbonifer and Epistominella exigua are common constituents. It is notable that the abundances of benthic foraminifera show marked decline between ~6N and ~7N. However, the abundance of E. exigua increases northward from the equator to ~6N, which is consistent to more significat seasonal fluctuation of chlorophyll-a concentrations in the surface water and confirms the seasonal food supply from the surface ocean at ~131W of the central equatorial Pacific Ocean. Latitudinal occurrences of benthic foraminifera during MIS 8 were basically similar to those of the present day.c foraminifera from six surface sediments of KODOS05-02 cruise along a transect at 131W, focusing on correspondence to the ITCZ position. Nuttallides umbonifer and Epistominella exigua are common constituents. It is notable that the abundances of benthic foraminifera show marked decline between ~6N and ~7N. However, the abundance of E. exigua increases northward from the equator to ~6N, which is consistent to more significat seasonal fluctuation of chlorophyll-a concentrations in the surface water and confirms the seasonal food supply from the surface ocean at ~131W of the central equatorial Pacific Ocean. Latitudinal occurrences of benthic foraminifera during MIS 8 were basically similar to those of the present day.