Mineral-catalysed formation of marine NO and N2O on the anoxic early Earth

Buessecker, Steffen; Imanaka, Hiroshi; Ely, Tucker; Hu, Renyu; Romaniello, Stephen J.; Cadillo‐Quiroz, Hinsby

doi:10.1038/s41561-022-01089-9

Cited by 12 publications

(11 citation statements)

References 79 publications

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“…The abiotic reaction between NO 3 − and Fe(II) (neither in dissolved nor solid forms), although thermodynamically feasible, hardly proceeds at room temperatures without catalyst 19,30,36 . By contrast, NO 2 − has long been recognized as a chemical oxidant for aqueous Fe 2+ ions 37 .…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it is reasonable to speculate that magnetite NPs modulate microbial nitrate reduction pathways via an interplay between the magnetite and the intermediate product NO 2 − . Compared with dissolved Fe( ), Fe( )-bearing minerals normally have a higher activity [19][20][21][22] . Speci cally for magnetite, electrons from its particle interior easily ow towards the surface at circum-neutral pH 39 .…”

Section: Discussionmentioning

confidence: 99%

“…In addition to soluble iron, the Proterozoic ocean also contained various suspended mixed-valent iron [Fe(II)-Fe(III)] minerals. Brie y, the massive preccipitation of mixed-valent iron minerals (e.g., green rust and magnetite) in the water column was ascribed to the interplay of photosynthesis-induced Fe 2+ oxidation and subsequent microbially-mediated or abiotic Fe(III) reduction [15][16][17][18][19] .…”

Section: Introductionmentioning

confidence: 99%

“…These primary iron minerals, exhibiting higher adsorption and redox-modulating activities compared to Fe 2+ ions [19][20][21][22] , have controlled the biogeochemical cycling of phosphorus and trace metals 23,24 . However, their effects on microbially-mediated N cycling remain largely unknown, especially under Paleoproterozoic oceanic conditions.…”

Section: Introductionmentioning

confidence: 99%

“…First, magnetite is widely distributed in Precambrian rocks, some of which have a sedimentary origin 17 . In modern ferruginous lakes like Paleoproterozoic oceans, such minerals have also been observed 16 , suggesting that primary authigenic magnetite NPs may be an important iron sink in the Paleoproterozoic oceans 17,19,[25][26][27][28] . Second, the presence of structurally-coordinated Fe( ) theoretically allows magnetite to act as a potential electron donor for microbial nitrate reduction, especially for magnetite NPs due to their nite-size effects 29,30 .…”

Section: Introductionmentioning

confidence: 99%

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Magnetite nanoparticles modulate microbial nitrate reduction pathways: Implications for nitrogen cycle in ferruginous oceans

Wang

Luo

Papineau

et al. 2023

Preprint

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Nitrogen (N) is an essential element for living organisms that limits the productivity of biospheres through time. It has been suggested that ferruginous anoxic waters could enhance the fraction of dissimilatory nitrate reduction to ammonium (DNRA) and conserve the biologically available N in the ecosystems. However, the role of mixed-valent iron [Fe(II)-Fe(III)] minerals (e.g., magnetite) in the microbially-mediated N cycle has been largely overlooked. Here we examine the microbial nitrate reduction in the presence/absence of magnetite nanoparticles (NPs) through a series of anaerobic bench experiments with a common denitrifying bacterium-Pseudogulbenkiania sp. strain 2002. Our results show that NH4+ yield is remarkably enhanced by the presence of magnetite NPs; otherwise the reduction products are mainly N2O/N2. Upon microbial nitrate reduction, magnetite NPs are partially oxidized to form a maghemite-magnetite solid solution. These findings demonstrate that magnetite NPs can partially modulate microbial nitrate reduction from denitrification to DNRA. This metabolic shift has significant implications for N retention in ferruginous water bodies that predominated the Precambrian oceans.

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Section: Discussionmentioning

confidence: 99%