Centennial changes in North Pacific anoxia linked to tropical trade winds

Science
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Abstract

Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ15N) from multiple sediment cores. Increasing δ15N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ15N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean’s largest anoxic zone will contract despite a global O2 decline.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Centennial changes in North Pacific anoxia linked to tropical trade winds
Series title Science
DOI 10.1126/science.1252332
Volume 345
Issue 6197
Year Published 2014
Language English
Publisher American Association for the Advancement of Science
Contributing office(s) Alaska Science Center
Description 4 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Science
First page 665
Last page 668
Other Geospatial North Pacific