Contribution of electroactive humic substances to the iron-binding ligands released during microbial remineralisation of sinking particles



Whitby, Hannah ORCID: 0000-0002-0064-3052, Bressac, Matthieu, Sarthou, Géraldine, Ellwood, Michael J, Guieu, Cécile and Boyd, Philip W
(2020) Contribution of electroactive humic substances to the iron-binding ligands released during microbial remineralisation of sinking particles. Geophysical Research Letters, 47 (7).

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Abstract

Microscopic plants and animals in seawater require nutrients to survive. One of these key nutrients is iron, dissolved in seawater at very low concentrations. The growth of around half of the microscopic life in the upper ocean is dependent on the availability of this dissolved iron. These organisms form the bottom of the food chain, and their growth is linked to marine productivity and the drawdown of carbon into the deep ocean, in turn influencing climate change. Because iron tends to not dissolve easily in seawater, it must bind with compounds known as ligands, which help keep iron dissolved. However, processes controlling the composition of this ligand pool are poorly understood. As material sinks through the water column, it is broken down by marine microbes, releasing iron and ligands. Here we have studied the release of iron, ligands, and a specific type of ligand known as humic substances, during the microbial degradation of sinking particles. By doing this, we have identified a large fraction of the released ligand pool. This furthers our understanding of the processes controlling dissolved iron concentrations and distributions in ocean waters, providing key information for biogeochemical modeling and for calculating carbon sequestration in seawater.

Item Type: Article
Uncontrolled Keywords: iron, ligand, humic, remineralisation, particle, degradation
Depositing User: Symplectic Admin
Date Deposited: 06 Apr 2020 10:26
Last Modified: 06 Jul 2022 18:10
DOI: 10.1029/2019gl086685
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3082102