Marine Fish Productivity Across the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM), a transient global warming event ~55 Ma, is one of the closest geologic analogues to modern-day climate change. Although the PETM is known to have triggered extinctions in deep-sea ecosystems and extensive biogeographic shifts, little work has been done on the response of higher-order marine vertebrates. This work presents mass accumulation data for fossil fish teeth (ichthyoliths) in three ODP/IODP pelagic sediment cores. In all three records, the initial stages of the PETM are associated with a significant transient increase in fish productivity, which may have peaked approximately 10,000 to 15,000 years after the onset of the PETM; the highest resolution data, from the Atlantic, suggests that this increase may have come after a period of significantly depressed productivity. Changes in net primary productivity, as determined from biogenic barium proxies, do not appear sufficient to fully explain the observed trends.