SCIENCE@home

Persistent eastern equatorial Pacific Ocean upwelling since the warm Pliocene.

P. Rafter,J. Farmer,A. Martínez-García,A. C. Ravelo,K. Karnauskas,F. Batista,S. Bernasconi,H. Ren,A. Auderset,G. Haug,D. Sigman

Published 2025 in Science

ABSTRACT

Upwelling generates a nutrient-rich "cold tongue" in the eastern equatorial Pacific Ocean (EEP), with impacts on global climate, oceanic biological productivity, and the carbon cycle. The cold tongue was reduced during the Pliocene Epoch, a feature attributed to weaker upwelling and an associated deepening of the surface mixed layer in the EEP. Here, we report nitrogen-isotope evidence that modern-like upwelling occurred in the EEP during the Pliocene and has persisted over the past 5 million years. We explain the reduced Pliocene cold tongue as an expression of the reduced temperature difference between surface and subsurface waters in the tropical Pacific. The attendant reduction in the vertical density gradient may have maintained EEP upwelling despite the expected slackening of the trade winds under Pliocene warmth.

PUBLICATION RECORD

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-46 of 46 references · Page 1 of 1

CITED BY