21-7 Deep sea biotic responses to the Neogene Indonesian Throughflow dynamics.

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

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The Indonesian Throughflow is a critical component of the global oceanographic and climatological system. However, our understanding of its impacts on the marine ecosystem remained limited, especially in the deep sea. Here we investigated a 10 million-year history of deep-sea benthic community changes of the northwestern Australian margin under the influence of the Indonesian Throughflow flowing into the Indian Ocean, situated at the southern margin of the Coral Triangle biodiversity hotspot, known to be the global center of marine biodiversity. Our results showed that the faunal composition during the Indonesian Throughflow restriction period (6.5–2.7 million years ago) was distinct from those of the pre- and post-restriction periods. The restriction of the Indonesian Throughflow caused substantial impacts on the regional deep-sea community, likely via temperature, dispersal possibility, and/or productivity change. We have an increasingly better understanding that ongoing and future human-induced climatic change will alter the global ocean circulation. Our paleobiological reconstruction alarms that the tropical deep-sea ecosystem, which could be highly biodiverse (e.g., as the deep-sea Coral Triangle in this region), is likely very sensitive to ocean circulation changes in the past, present, and future.

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

doi: 10.1130/abs/2025AM-5436

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