Unprecedented Fe delivery from the Congo River margin to the South Atlantic Gyre

Rivers are a major supplier of particulate and dissolved material to the ocean, but their role as sources of bio-essential dissolved iron (dFe) is thought to be limited due to rapid, efficient Fe removal during estuarine mixing. Here, we use trace element and radium isotope data to show that the inf...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Vieira, Lúcia H., Krisch, Stephan, Hopwood, Mark J., Beck, Aaron J., Scholten, Jan, Liebetrau, Volker, Achterberg, Eric P.
Format: Text
Language:English
Published: Nature Publishing Group UK 2020
Subjects:
Article
South Atlantic Ocean
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987306/
http://www.ncbi.nlm.nih.gov/pubmed/31992707
https://doi.org/10.1038/s41467-019-14255-2
Description
Summary:Rivers are a major supplier of particulate and dissolved material to the ocean, but their role as sources of bio-essential dissolved iron (dFe) is thought to be limited due to rapid, efficient Fe removal during estuarine mixing. Here, we use trace element and radium isotope data to show that the influence of the Congo River margin on surface Fe concentrations is evident over 1000 km from the Congo outflow. Due to an unusual combination of high Fe input into the Congo-shelf-zone and rapid lateral transport, the Congo plume constitutes an exceptionally large offshore dFe flux of 6.8 ± 2.3 × 10(8) mol year(−1). This corresponds to 40 ± 15% of atmospheric dFe input into the South Atlantic Ocean and makes a higher contribution to offshore Fe availability than any other river globally. The Congo River therefore contributes significantly to relieving Fe limitation of phytoplankton growth across much of the South Atlantic.

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