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Shell fluxes of solution‐resistant planktonic foraminifers as a proxy for mixed‐layer depth
Author(s) -
Itou Masashi,
Noriki Shinichiro
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl014693
Subject(s) - foraminifera , shell (structure) , plankton , subtropics , geology , monsoon , flux (metallurgy) , mixed layer , series (stratigraphy) , oceanography , sea surface temperature , climatology , atmospheric sciences , paleontology , materials science , biology , ecology , composite material , benthic zone , metallurgy
Shell fluxes of solution‐resistant planktonic foraminifera, G. scitula and N. dutertrei , collected by moored sediment traps, are examined as a possible tool to reconstruct the surface water convection in the past subtropical western North Pacific. Time‐series observation reveals that shell fluxes of these two species fluctuate in an opposite sense. When surface water is warmed and well stratified, N. dutertrei fluxes reach a maximum. In contrast, G. scitula increases in response to the deepening of the mixed‐layer. To amplify the response of shell fluxes to climatological variables, the shell flux ratio of G. scitula to N. dutertrei ( F G.sci/N.dut ) is introduced. The time series F G.sci/N.dut pattern is similar to that of the Monsoon Index (MOI) representing the strength of the East Asian Winter Monsoon. The F G.sci/N.dut is also well correlated with the mixed‐layer depth. These correlations allow reconstruction of the ancient MOI and MLD from the faunal ratio.