Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean.

ABSTRACT: While chromium stable isotopes (δ⁵³Cr) have received significant attention for their utility as a tracer of oxygen availability in the distant geological past, a mechanistic understanding of modern oceanic controls on Cr and δ⁵³Cr is still lacking. Here we present total dissolved δ⁵³Cr, concentrations of Cr (III) and total dissolved Cr, and net community productivity (NCP) from the North Pacific. Chromium concentrations show surface depletions in waters with elevated NCP, but not in lower productivity waters. Observed Cr deficits correspond well with calculated Cr export derived from NCP and Cr:C ratios of natural phytoplankton and marine particulates. Chromium (III) concentrations are stable over the diel cycle yet correlate with NCP, with maxima found in

SUBMITTER: Janssen DJ 

PROVIDER: S-EPMC7375040 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature