148-9 A Plankton’s View of the Kuroshio Current Extension across the Mid-Piacenzian Warm Period

Session: Insights from Microfossils and Their Modern Analogs: From Traditional to Emerging Approaches (Posters)

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The Kuroshio Current Extension (KCE) is a current system off the Japanese coast that significantly influences the local Japanese and Western United States atmosphere. When the KCE meets the subpolar western boundary current, the Oyashio Current, they create an organismal boundary, fostering an environment with high species diversity. Studies of this current system have shown that during warmer periods in Earth’s history, the current shifts northward. Studies have also shown that this area has warmed two to three times faster than global sea surface temperatures, which has altered organism distribution, atmospheric dynamics, and the surrounding ecology. These drastic changes pose severe ecological and, subsequently, economic consequences for Japan, which heavily relies on the resources from this area. Foraminifera, marine zooplankton with calcareous shells, serve as proxies for inferring paleoceanographic behavior in response to paleoenvironmental events. As temperature-sensitive organisms, they track their preferred environments. By analyzing the community composition of fossil foraminifera recovered from deep sea sediment cores during geologically warmer times, surface ocean dynamics can be reconstructed. The mid-Piacenzian Warm Period (mPWP) was an interval of increased warming roughly 3.3 million years ago. The mPWP acts as a benchmark for assessing ocean warming as it resembles our current Earth’s carbon levels. In analyzing fossil plankton assemblages from KCE across the mPWP, the response of the KCE to analogous warming can be tracked, which is crucial to understanding future responses under climate change.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9148

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