Centennial OMZ changes in the NW Mexican Margin from geochemical and foraminiferal sedimentary records

TitleCentennial OMZ changes in the NW Mexican Margin from geochemical and foraminiferal sedimentary records
Publication TypeJournal Article
Year of Publication2019
AuthorsOntiveros-Cuadras J.F., Thunell RC, Ruiz-Fernández A.C., Benitez-Nelson CR, Machain-Castillo M.L., Tappa E, Sanchez-Cabeza J.A.
JournalContinental Shelf Research
Volume176
Pagination64-75
Abstract

Oxygen minimum zones (OMZs) are predicted to expand in the near future due to continued global warming, with largest declines in oxygen occurring within the strong tropical OMZs. In this study, shifts in the position and intensity of the OMZ in the Eastern Tropical North Pacific (ETNP) were examined using three 210Pb-dated sediment cores collected along the continental shelf and slope of the NW Mexican Margin (southwest of Mazatlán). Using a suite of redox sensitive elements, bulk element and physical analyses, three main factors were identified as driving the geochemical signatures of trace elements across the NW Mexican Margin: 1) terrigenous input, 2) organic matter scavenging and 3) bottom water oxygen content. Downcore trends in benthic foraminiferal assemblages and authigenic concentrations of Mo and U suggest that dysoxic conditions were more intense and covered a larger depth range prior to the 20th century followed by a reduction in both size and strength of the OMZ over the last century.

DOI10.1016/j.csr.2019.02.009
Refereed DesignationRefereed

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