Pliocene decoupling of equatorial Pacific temperature and pH gradients
Ocean dynamics per 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 verso 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 a 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 con the east Pacific 13,14,15 that typically results from stronger upwelling. Here we reconcile these observations by providing new evidence for per radically different-from-modern circulation velocita con the early Pliocene/late Miocene 16 that results per older, more acidic and more nutrient-rich tazza reaching the equatorial Pacific. These results provide a mechanism for enhanced productivity durante the early Pliocene/late Miocene east Pacific even sopra the presence of weaker wind-driven upwelling. Our findings shed new light on equatorial Pacific dynamics and help puro constrain the potential changes they will undergo con the near future, given that the Earth is expected preciso reach Pliocene-like levels of warming durante the next century.
