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The Kuroshio Current Extension (KCE) is a major western boundary current as part of the North Pacific Subtropical Gyre. Such currents are currently warming at a rate 2-3 times faster than other regions in the world ocean. Observational sea surface temperature data from the past century have concluded that the KCE has warmed by approximately 1-2℃. Previous studies have utilized warm periods during the Pliocene to determine that the current may have warmed 3-4℃. Thus, it is imperative to quantify the behavior of the KCE under increased warming, such as using analogue warm periods in Earth’s past like the mid-Piacenzian Warm Period (mPWP). This study uses stable isotopic data from two species of thermocline-dwelling planktic foraminifera (Globoconella inflata and Neogloboquadrina incompta), from Ocean Drilling Program Hole 1207A, located on the northern edge of the KCE. Such data is used to characterize the behavior of the thermocline within the KCE through the Pliocene. This will be the first stable isotopic record to investigate the behavior of the KCE across the mPWP at a high resolution (~3 thousand years). In addition, we investigate how paleoecology of thermocline-dwelling planktic foraminifera affects the interpretations of geochemical records through time. Specifically, we compare stable isotopic records obtained from species that grow during the winter months (G. inflata) to that of a species present year-round in the KCE (N. incompta).



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Using Paleoecology of Planktic Foraminifera to Interpret the Thermocline Behavior of the Kuroshio Current Extension across the Mid-Piacenzian Warm Period