Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods.

ABSTRACT: Changes in bioavailable dust-borne iron (Fe) supply to the iron-limited Southern Ocean may influence climate by modulating phytoplankton growth and CO₂ fixation into organic matter that is exported to the deep ocean. The chemical form (speciation) of Fe impacts its bioavailability, and glacial weathering produces highly labile and bioavailable Fe minerals in modern dust sources. However, the speciation of dust-borne Fe reaching the iron-limited Southern Ocean on glacial-interglacial timescales is unknown, and its impact on the bioavailable iron supply over geologic time has not been quantified. Here we use X-ray absorption spectroscopy on subantarctic South Atlantic and South Pacific marine sediments to reconstruct dust-borne Fe speciation over the last glacial cycle, and determ

SUBMITTER: Shoenfelt EM 

PROVIDER: S-EPMC6217405 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature