Oxidation of iodide to iodate by cultures of marine ammonia-oxidising bacteria

Hughes, Claire, Barton, Eleanor, Hepach, Helmke, Chance, Rosie, Pickering, Matthew D., Hogg, Karen, Pommerening-Röser, Andreas, Wadley, Martin R., Stevens, David P. ORCID: https://orcid.org/0000-0002-7283-4405 and Jickells, Tim D. (2021) Oxidation of iodide to iodate by cultures of marine ammonia-oxidising bacteria. Marine Chemistry, 234. ISSN 0304-4203

[thumbnail of Accepted_manuscript]
PDF (Accepted_manuscript) - Accepted Version
Available under License Creative Commons Attribution Non-commercial No Derivatives.

Download (1MB) | Preview


Reaction with iodide (I−) at the sea surface is an important sink for atmospheric ozone, and causes sea-air emission of reactive iodine which in turn drives further ozone destruction. To incorporate this process into chemical transport models, improved understanding of the factors controlling marine iodine speciation, and especially sea-surface iodide concentrations, is needed. The oxidation of I− to iodate (IO3−) is the main sink for oceanic I−, but the mechanism for this remains unknown. We demonstrate for the first time that marine nitrifying bacteria mediate I− oxidation to IO3−. A significant increase in IO3− concentrations compared to media-only controls was observed in cultures of the ammonia-oxidising bacteria Nitrosomonas sp. (Nm51) and Nitrosoccocus oceani (Nc10) supplied with 9–10 mM I−, indicating I− oxidation to IO3−. Cell-normalised production rates were 15.69 (±4.71) fmol IO3− cell−1 d−1 for Nitrosomonas sp., and 11.96 (±6.96) fmol IO3− cell−1 d−1 for Nitrosococcus oceani, and molar ratios of iodate-to-nitrite production were 9.2 ± 4.1 and 1.88 ± 0.91 respectively. Preliminary experiments on nitrite-oxidising bacteria showed no evidence of I− to IO3− oxidation. If the link between ammonia and I− oxidation observed here is representative, our ocean iodine cycling model predicts that future changes in marine nitrification could alter global sea surface I− fields with potential implications for atmospheric chemistry and air quality.

Item Type: Article
Uncontrolled Keywords: sdg 14 - life below water ,/dk/atira/pure/sustainabledevelopmentgoals/life_below_water
Faculty \ School: Faculty of Science > School of Mathematics
Faculty of Science > School of Environmental Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups: Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Faculty of Science > Research Groups > Fluid and Solid Mechanics
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 24 Jun 2021 00:11
Last Modified: 22 May 2024 01:17
URI: https://ueaeprints.uea.ac.uk/id/eprint/80321
DOI: 10.1016/j.marchem.2021.104000


Downloads per month over past year

Actions (login required)

View Item View Item