Oxygen intrusions sustain aerobic nitrite-oxidizing bacteria in anoxic marine zones

Buchanan, Pearse; Sun, Xin; Weissman, Jake L.; Zakem, Emily

doi:10.1101/2023.02.22.529547

Cited by 7 publications

(4 citation statements)

References 98 publications

(228 reference statements)

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“…This in turn broadens the overlap between aerobic (e.g., Figure 2a) and anaerobic metabolisms (Figures 2b–2d; see also Buchanan et al. (2023)), and favors metabolite exchange.…”

Section: Discussionmentioning

confidence: 79%

“…Notably, eddies enhance chemical variability and tracer transport (Damien et al, 2023;Gruber et al, 2011), causing both intrusions of oxygenated waters into the core of the OMZ, and anoxic fluctuations along the OMZ margins . This in turn broadens the overlap between aerobic (e.g., Figure 2a) and anaerobic metabolisms (Figures 2b-2d; see also Buchanan et al (2023)), and favors metabolite exchange.…”

Section: Discussionmentioning

confidence: 91%

See 1 more Smart Citation

Mesoscale Eddy Variability Enhances Fixed Nitrogen Loss and Suppresses Nitrous Oxide Production in Oxygen Minimum Zones

McCoy,

Damien,

Yang

et al. 2024

Geophysical Research Letters

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Within oxygen minimum zones, anaerobic processes transform bioavailable nitrogen (N) into the gases dinitrogen (N2) and nitrous oxide (N2O), a potent greenhouse gas. Mesoscale eddies in these regions create heterogeneity in dissolved N tracers and O2 concentrations, influencing nonlinear N cycle reactions that depend on them. Here, we use an eddy‐resolving model of the Eastern Tropical South Pacific to show that eddies enhance N2 production by between 43% and 64% at the expense of reducing N2O production by between 94% and 104% due to both the steep increase of progressive denitrification steps at vanishing oxygen, and the more effective inhibition of N2O consumption relative to production. Our findings reveal the critical role of eddies in shaping the N cycle of oxygen minimum zones, which is not currently represented by coarse models used for climate studies.

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“…This in turn broadens the overlap between aerobic (e.g., Figure 2a) and anaerobic metabolisms (Figures 2b–2d; see also Buchanan et al. (2023)), and favors metabolite exchange.…”

Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 91%

Mesoscale Eddy Variability Enhances Fixed Nitrogen Loss and Suppresses Nitrous Oxide Production in Oxygen Minimum Zones

McCoy,

Damien,

Yang

et al. 2024

Geophysical Research Letters

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“…A widespread influence of nitrite oxidation in marine ODZs (T.S. Martin et al, 2019a;Babbin et al, 2020;Buchanan et al, 2023;Sun et al, 2023) thus suggests that the isotope effect for water column denitrification is likely lower than 25‰, which would require less benthic denitrification to balance the N isotope budget.…”

Section: Understanding Nitrogen Cycling and Loss In Oxygen Deficient ...mentioning

confidence: 99%

Advances in Understanding the Marine Nitrogen Cycle in the GEOTRACES Era

Casciotti,

Marshall,

Fawcett

et al. 2024

Oceanog

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Because nitrogen availability limits primary production over much of the global ocean, understanding the controls on the marine nitrogen inventory and supply to the surface ocean is essential for understanding biological productivity and exchange of greenhouse gases with the atmosphere. Quantifying the ocean’s inputs, outputs, and internal cycling of nitrogen requires a variety of tools and approaches, including measurements of the nitrogen isotope ratio in organic and inorganic nitrogen species. The marine nitrogen cycle, which shapes nitrogen availability and speciation in the ocean, is linked to the elemental cycles of carbon, phosphorus, and trace elements. For example, the majority of nitrogen cycle oxidation and reduction reactions are mediated by enzymes that require trace metals for catalysis. Recent observations made through global-scale programs such as GEOTRACES have greatly expanded our knowledge of the marine nitrogen cycle. Though much work remains to be done, here we outline key advances in understanding the marine nitrogen cycle that have been achieved through these analyses, such as the distributions and rates of dinitrogen fixation, terrestrial nitrogen inputs, and nitrogen loss processes.

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“…14). Many hypotheses have been proposed to explain the observed anaerobic nitrite oxidation, including alternative oxidants like iodate (Babbin et al, 2017), distinct nitrite oxidizers that are only present in the oxygen-minimum zones (OMZs) and that are adapted to the low-oxygen conditions (Sun et al, 2021), van de Leemput et al, 2011;Babbin et al, 2020;Tracey et al, 2023) and oxygen intrusions (Buchanan et al, 2023). Whether nitrite oxidation is truly anaerobic and how nitrite oxidation is sustained in oxygen-depleted waters remain to be determined.…”

Section: Distribution Of Nitrite Oxidationmentioning

confidence: 99%

Database of nitrification and nitrifiers in the global ocean

Tang,

Ward,

Beman

et al. 2023

Earth Syst. Sci. Data

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Abstract. As a key biogeochemical pathway in the marine nitrogen cycle, nitrification (ammonia oxidation and nitrite oxidation) converts the most reduced form of nitrogen – ammonium–ammonia (NH4+–NH3) – into the oxidized species nitrite (NO2-) and nitrate (NO3-). In the ocean, these processes are mainly performed by ammonia-oxidizing archaea (AOA) and bacteria (AOB) and nitrite-oxidizing bacteria (NOB). By transforming nitrogen speciation and providing substrates for nitrogen removal, nitrification affects microbial community structure; marine productivity (including chemoautotrophic carbon fixation); and the production of a powerful greenhouse gas, nitrous oxide (N2O). Nitrification is hypothesized to be regulated by temperature, oxygen, light, substrate concentration, substrate flux, pH and other environmental factors. Although the number of field observations from various oceanic regions has increased considerably over the last few decades, a global synthesis is lacking, and understanding how environmental factors control nitrification remains elusive. Therefore, we have compiled a database of nitrification rates and nitrifier abundance in the global ocean from published literature and unpublished datasets. This database includes 2393 and 1006 measurements of ammonia oxidation and nitrite oxidation rates and 2242 and 631 quantifications of ammonia oxidizers and nitrite oxidizers, respectively. This community effort confirms and enhances our understanding of the spatial distribution of nitrification and nitrifiers and their corresponding drivers such as the important role of substrate concentration in controlling nitrification rates and nitrifier abundance. Some conundrums are also revealed, including the inconsistent observations of light limitation and high rates of nitrite oxidation reported from anoxic waters. This database can be used to constrain the distribution of marine nitrification, to evaluate and improve biogeochemical models of nitrification, and to quantify the impact of nitrification on ecosystem functions like marine productivity and N2O production. This database additionally sets a baseline for comparison with future observations and guides future exploration (e.g., measurements in the poorly sampled regions such as the Indian Ocean and method comparison and/or standardization). The database is publicly available at the Zenodo repository: https://doi.org/10.5281/zenodo.8355912 (Tang et al., 2023).

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Oxygen intrusions sustain aerobic nitrite-oxidizing bacteria in anoxic marine zones

Cited by 7 publications

References 98 publications

Mesoscale Eddy Variability Enhances Fixed Nitrogen Loss and Suppresses Nitrous Oxide Production in Oxygen Minimum Zones

Mesoscale Eddy Variability Enhances Fixed Nitrogen Loss and Suppresses Nitrous Oxide Production in Oxygen Minimum Zones

Advances in Understanding the Marine Nitrogen Cycle in the GEOTRACES Era

Database of nitrification and nitrifiers in the global ocean

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