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Article: Iron-dependent nitrogen cycling in a ferruginous lake and the nutrient status of Proterozoic oceans

TitleIron-dependent nitrogen cycling in a ferruginous lake and the nutrient status of Proterozoic oceans
Authors
Issue Date2017
Citation
Nature Geoscience, 2017, v. 10, n. 3, p. 217-221 How to Cite?
AbstractNitrogen limitation during the Proterozoic has been inferred from the great expanse of ocean anoxia under low-O 2 atmospheres, which could have promoted NO 3 â ' reduction to N 2 and fixed N loss from the ocean. The deep oceans were Fe rich (ferruginous) during much of this time, yet the dynamics of N cycling under such conditions remain entirely conceptual, as analogue environments are rare today. Here we use incubation experiments to show that a modern ferruginous basin, Kabuno Bay in East Africa, supports high rates of NO 3 â ' reduction. Although 60% of this NO 3 â ' is reduced to N 2 through canonical denitrification, a large fraction (40%) is reduced to NH 4 +, leading to N retention rather than loss. We also find that NO 3 â ' reduction is Fe dependent, demonstrating that such reactions occur in natural ferruginous water columns. Numerical modelling of ferruginous upwelling systems, informed by our results from Kabuno Bay, demonstrates that NO 3 â ' reduction to NH 4 + could have enhanced biological production, fuelling sulfate reduction and the development of mid-water euxinia overlying ferruginous deep oceans. This NO 3 â ' reduction to NH 4 + could also have partly offset a negative feedback on biological production that accompanies oxygenation of the surface ocean. Our results indicate that N loss in ferruginous upwelling systems may not have kept pace with global N fixation at marine phosphorous concentrations (0.04-0.13 μM) indicated by the rock record. We therefore suggest that global marine biological production under ferruginous ocean conditions in the Proterozoic eon may thus have been P not N limited.
Persistent Identifierhttp://hdl.handle.net/10722/269759
ISSN
2017 Impact Factor: 14.391
2015 SCImago Journal Rankings: 7.297

 

DC FieldValueLanguage
dc.contributor.authorMichiels, Céline C.-
dc.contributor.authorDarchambeau, François-
dc.contributor.authorRoland, Fleur A.E.-
dc.contributor.authorMorana, Cédric-
dc.contributor.authorLlirós, Marc-
dc.contributor.authorGarcía-Armisen, Tamara-
dc.contributor.authorThamdrup, Bo-
dc.contributor.authorBorges, Alberto V.-
dc.contributor.authorCanfield, Donald E.-
dc.contributor.authorServais, Pierre-
dc.contributor.authorDescy, Jean Pierre-
dc.contributor.authorCrowe, Sean A.-
dc.date.accessioned2019-04-30T01:49:30Z-
dc.date.available2019-04-30T01:49:30Z-
dc.date.issued2017-
dc.identifier.citationNature Geoscience, 2017, v. 10, n. 3, p. 217-221-
dc.identifier.issn1752-0894-
dc.identifier.urihttp://hdl.handle.net/10722/269759-
dc.description.abstractNitrogen limitation during the Proterozoic has been inferred from the great expanse of ocean anoxia under low-O 2 atmospheres, which could have promoted NO 3 â ' reduction to N 2 and fixed N loss from the ocean. The deep oceans were Fe rich (ferruginous) during much of this time, yet the dynamics of N cycling under such conditions remain entirely conceptual, as analogue environments are rare today. Here we use incubation experiments to show that a modern ferruginous basin, Kabuno Bay in East Africa, supports high rates of NO 3 â ' reduction. Although 60% of this NO 3 â ' is reduced to N 2 through canonical denitrification, a large fraction (40%) is reduced to NH 4 +, leading to N retention rather than loss. We also find that NO 3 â ' reduction is Fe dependent, demonstrating that such reactions occur in natural ferruginous water columns. Numerical modelling of ferruginous upwelling systems, informed by our results from Kabuno Bay, demonstrates that NO 3 â ' reduction to NH 4 + could have enhanced biological production, fuelling sulfate reduction and the development of mid-water euxinia overlying ferruginous deep oceans. This NO 3 â ' reduction to NH 4 + could also have partly offset a negative feedback on biological production that accompanies oxygenation of the surface ocean. Our results indicate that N loss in ferruginous upwelling systems may not have kept pace with global N fixation at marine phosphorous concentrations (0.04-0.13 μM) indicated by the rock record. We therefore suggest that global marine biological production under ferruginous ocean conditions in the Proterozoic eon may thus have been P not N limited.-
dc.languageeng-
dc.relation.ispartofNature Geoscience-
dc.titleIron-dependent nitrogen cycling in a ferruginous lake and the nutrient status of Proterozoic oceans-
dc.typeArticle-
dc.description.natureLink_to_subscribed_fulltext-
dc.identifier.doi10.1038/ngeo2886-
dc.identifier.scopuseid_2-s2.0-85014392438-
dc.identifier.volume10-
dc.identifier.issue3-
dc.identifier.spage217-
dc.identifier.epage221-
dc.identifier.eissn1752-0908-

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