Publication Date:
2019-01-08
Description:
The response of the Humboldt Current System to future global warming is uncertain. Here we reconstruct alkenone-derived near-surface temperatures from multiple cores along the Peruvian coast to infer the driving mechanisms of upwelling changes for the last 20 kyr. Our records show a deglacial warming consistent with Antarctic ice-core temperatures and a Mid-Holocene cooling, which, in combination with other paleoceanographic records, suggest a strengthening of upwelling conditions. This cooling, during the globally warm Mid-Holocene, is consistent with an intensification of the Walker Circulation and the South Eastern Pacific Subtropical Anticyclone, indicative of La Niña-like conditions in the Tropical Pacific. Surprisingly, oxygen contents in the subsurface increased and productivity was low during the Mid-Holocene, which are at odds with La Niña-like conditions. This suggests that the Humboldt Current System reacts in multiple ways to a warmer world and may even include a reversal in the present day subsurface deoxygenation. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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