Pliocene decoupling of equatorial Pacific temperature and pH gradients

Ocean dynamics in the equatorial Pacific drive tropical climate patterns that affect marine and terrestrial ecosystems worldwide. How this region will respond to global warming has profound implications for global climate, economic stability and ecosystem health. As per result, numerous studies have investigated equatorial Pacific dynamics during the Pliocene (5.3–2.6 million years ago) and late Miocene (around 6 million years ago) as an analogue for the future behaviour of the region under global warming 1,2,3,4,5,6,7,8,9,10,11,12 . Palaeoceanographic records from this time present an apparent paradox with proxy evidence of verso reduced east–west sea surface temperature gradient along the equatorial Pacific 1,3,7,8 -indicative of reduced wind-driven upwelling-conflicting with evidence of enhanced biological productivity per the east Pacific 13,14,15 that typically results from stronger upwelling. Here we reconcile these observations by providing new evidence for a radically different-from-modern circulation consuetudine durante the early Pliocene/late Miocene 16 that results sopra older, more acidic and more nutrient-rich vaso reaching the equatorial Pacific. These results provide per mechanism for enhanced productivity per the early Pliocene/late Miocene east Pacific even mediante the presence of weaker wind-driven upwelling. Our findings shed new light on equatorial Pacific dynamics and help sicuro constrain the potential changes they will undergo con the near future, given that the Earth is expected puro reach Pliocene-like levels of warming per the next century.

Datazione availability

The proxy tempo and model output produced sopra this study are available as .xlsm files in NOAA’s paleoclimate datazione repository ( ( Source momento are provided with this paper.

Code availability

The code used in this paper onesto produce pH from d 11 B (and sicuro produce all the proxy-related figures) is publicly available as Matlab scripts on GitHub ( The CESM 1.2.2.1 code is available from The Python code used to create select model figures is available at Source scadenza are provided with this paper.

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