Ecological control of nitrite in the upper ocean
Author(s)
Al-Haj, Alia; Church, Matthew J.; van Dijken, Gert L.; Foster, Sarah Q.; Fulweiler, Robinson W.; Mills, Matthew M.; Zakem, Emily Juliette; Dutkiewicz, Stephanie; Follows, Michael J; ... Show more Show less
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Microorganisms oxidize organic nitrogen to nitrate in a series of steps. Nitrite, an intermediate product, accumulates at the base of the sunlit layer in the subtropical ocean, forming a primary nitrite maximum, but can accumulate throughout the sunlit layer at higher latitudes. We model nitrifying chemoautotrophs in a marine ecosystem and demonstrate that microbial community interactions can explain the nitrite distributions. Our theoretical framework proposes that nitrite can accumulate to a higher concentration than ammonium because of differences in underlying redox chemistry and cell size between ammonia- and nitrite-oxidizing chemoautotrophs. Using ocean circulation models, we demonstrate that nitrifying microorganisms are excluded in the sunlit layer when phytoplankton are nitrogen-limited, but thrive at depth when phytoplankton become light-limited, resulting in nitrite accumulation there. However, nitrifying microorganisms may coexist in the sunlit layer when phytoplankton are iron- or light-limited (often in higher latitudes). These results improve understanding of the controls on nitrification, and provide a framework for representing chemoautotrophs and their biogeochemical effects in ocean models.
Date issued
2018-03Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary SciencesJournal
Nature Communications
Publisher
Nature Publishing Group
Citation
Zakem, Emily J. et al. “Ecological Control of Nitrite in the Upper Ocean.” Nature Communications 9, 1 (March 2018): 1206 © 2018 The Author(s)
Version: Final published version
ISSN
2041-1723