Abundant porewater Mn(III) is a major component of the sedimentary redox system

Andrew S. Madison, Bradley M. Tebo, Alfonso Mucci, Bjørn Sundby, George W. Luther

Research output: Contribution to journalArticle

122 Scopus citations

Abstract

Soluble manganese(III) [Mn(III)] can potentially serve as both oxidant and reductant in one-electron-transfer reactions with other redox species. In near-surface sediment porewater, it is often overlooked as a major component of Mn cycling. Applying a spectrophotometric kinetic method to hemipelagic sediments from the Laurentian Trough (Quebec, Canada), we found that soluble Mn(III), likely stabilized by organic or inorganic ligands, accounts for up to 90% of the total dissolved Mn pool. Vertical profiles of dissolved oxygen and dissolved and solid Mn suggest that soluble Mn(III) is primarily produced via oxidation of Mn(II) diffusing upwards from anoxic sediments with lesser contributions from biotic and abiotic reductive dissolution of MnO2. The conceptual model of the sedimentary redox cycle should therefore explicitly include dissolved Mn(III).

Original languageEnglish (US)
Pages (from-to)875-878
Number of pages4
JournalScience
Volume341
Issue number6148
DOIs
StatePublished - Jan 1 2013

ASJC Scopus subject areas

  • General

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