title: Oceanography. Centennial changes in North Pacific anoxia linked to tropical trade winds.
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 (δ(15)N) from multiple sediment cores. Increasing δ(15)N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ(15)N 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.
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA, USA. cdeutsch@uw.edu.
authors.forename: Curtis
authors.initials: C
authors.lastname: Deutsch
authors.affiliation: Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA.
authors.forename: William
authors.initials: W
authors.lastname: Berelson
authors.affiliation: Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Thunell
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weber
authors.affiliation: Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Tems
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: James
authors.initials: J
authors.lastname: McManus
authors.affiliation: U.S. Geological Survey, University of Washington School of Oceanography, Seattle, WA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Crusius
authors.affiliation: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Taka
authors.initials: T
authors.lastname: Ito
authors.affiliation: Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California, México.
authors.forename: Timothy
authors.initials: T
authors.lastname: Baumgartner
authors.affiliation: Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California, México.
authors.forename: Vicente
authors.initials: V
authors.lastname: Ferreira
authors.affiliation: Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA. Department of Physical Sciences, Kingsborough Community College, City University of New York, New York, NY, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Mey
authors.affiliation: Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: van Geen
mesh_terms: D000693:Anaerobiosis; D058440:Denitrification; D057232:Global Warming; D010100:Oxygen / Q000032:analysis*; D010140:Pacific Ocean; D012623:Seawater / Q000737:chemistry*; D014329:Tropical Climate; D014919:Wind
chemical_list: D010100:Oxygen