Aerobic and anaerobic ammonia oxidizing bacteria – competitors or natural partners?

Schmidt, I

doi:10.1016/s0168-6496(01)00208-2

Cited by 46 publications

(61 citation statements)

References 41 publications

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“…During the past decade or so, suggested microbially mediated pathways for oxidation : reduction reactions involving N have been shown or proposed to occur in aquatic environments (e.g., Luther et al 1997;Hulth et al 1999;Schmidt et al 2002). Microbial processes are the most likely cause for the N loss at our study site, as opposed to adsorption to sediment, because the isotopic enrichment factor is positive for adsorption and would therefore result in a decrease in d 15 N of the residual material (Karamanos and Rennie 1978).…”

Section: Resultsmentioning

confidence: 85%

Nitrogen biogeochemistry of submarine groundwater discharge

Kroeger

Charette

2008

Limnology & Oceanography

196

190

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To investigate the role of the seepage zone in transport, chemical speciation, and attenuation of nitrogen loads carried by submarine groundwater discharge, we collected nearshore groundwater samples (n 5 328) and examined the distribution and isotopic signature (d 15 N) of nitrate and ammonium. In addition, we estimated nutrient fluxes from terrestrial and marine groundwater sources. We discuss our results in the context of three aquifer zones: a fresh groundwater zone, a shallow salinity transition zone (STZ), and a deep STZ. Groundwater plumes containing nitrate and ammonium occurred in the freshwater zone, whereas the deep STZ carried almost exclusively ammonium. The distributions of redox-cycled elements were consistent with theoretical thermodynamic stability of chemical species, with sharp interfaces between water masses of distinct oxidation : reduction potential, suggesting that microbial transformations of nitrogen were rapid relative to dispersive mixing. In limited locations in which overlap occurs between distribution of nitrate with that of ammonium and dissolved . Loss of nitrogen was not apparent in the shallow STZ, perhaps because of short water residence time. Despite organic Cpoor conditions, the nearshore aquifer and subterranean estuary are biogeochemically active zones, where attenuation of N loads can occur. Extent of attenuation is controlled by the degree of mixing of biogeochemically dissimilar water masses, highlighting the critical role of hydrogeology in N biogeochemistry. Mixing is related in part to thinning of the freshwater lens before discharge and to dispersion at the fresh : saline groundwater interface, features common to all submarine groundwater discharge zones.

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Section: Resultsmentioning

confidence: 85%

Nitrogen biogeochemistry of submarine groundwater discharge

Kroeger

Charette

2008

Limnology & Oceanography

196

190

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“…From the thermodynamic argument given above we conclude that it appears more likely that low-oxygen nitrification stops at the NO − 2 level, providing NO − 2 rather than NH + 4 to anammox (e.g. Schmidt et al, 2002) via diffusion of substrates into suboxic layers. Anyway, the NH + 4 invading suboxic waters from above is of heterotrophic origin from the oxic remineralisation of organic matter and hence should be accompanied by diffusive fluxes of respiratory CO 2 , similar as in an anoxic system underlying suboxic zones discussed above.…”

Section: Allochthonous Substrate Sourcesmentioning

confidence: 83%

Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

Koeve

Kähler

2010

Biogeosciences

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Abstract. The conversion of fixed nitrogen to N 2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO 2 . At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N 2 -production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO 2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ) focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N 2 -production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy ( CO 2 : N 2 ), varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic Nconversions are supported by diffusive fluxes of NH + 4 originating from neighbouring waters with sulphate reduction, much lower values of CO 2 : N 2 can be found. However, accounting for concomitant diffusive fluxes of CO 2 , the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic nature of suboxic N-conversions on the marine carbon cycle.

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“…Aerobic, chemolithoautotrophic bacteria within the Beta-and Gammaproteobacteria were the only known ammoniaoxidizing microorganisms (1,2). However, in the last few years, this understanding has been radically changed, first, by the discovery that ammonium can also be oxidized anaerobically by a clade of deep branching planctomycetes (3,4), and later by the equally surprising cultivation of ammonia-oxidizing archaea (AOA) belonging to the Crenarchaeota (5). Since then, AOA were found to outnumber ammonia-oxidizing bacteria (AOB) in several terrestrial and marine systems, including different soils (6), the North Sea and Atlantic Ocean (7), the Pacific Ocean (8), and the Black Sea (9).…”

mentioning

confidence: 99%

A moderately thermophilic ammonia-oxidizing crenarchaeote from a hot spring

Hatzenpichler¹,

Лебедева

Spieck

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

630

541

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The recent discovery of ammonia-oxidizing archaea (AOA) dramatically changed our perception of the diversity and evolutionary history of microbes involved in nitrification. In this study, a moderately thermophilic (46°C) ammonia-oxidizing enrichment culture, which had been seeded with biomass from a hot spring, was screened for ammonia oxidizers. Although gene sequences for crenarchaeotal 16S rRNA and two subunits of the ammonia monooxygenase (amoA and amoB) were detected via PCR, no hints for known ammonia-oxidizing bacteria were obtained. Comparative sequence analyses of these gene fragments demonstrated the presence of a single operational taxonomic unit and thus enabled the assignment of the amoA and amoB sequences to the respective 16S rRNA phylotype, which belongs to the widely distributed group I.1b (soil group) of the Crenarchaeota. Catalyzed reporter deposition (CARD)-FISH combined with microautoradiography (MAR) demonstrated metabolic activity of this archaeon in the presence of ammonium. This finding was corroborated by the detection of amoA gene transcripts in the enrichment. CARD-FISH/ MAR showed that the moderately thermophilic AOA is highly active at 0.14 and 0.79 mM ammonium and is partially inhibited by a concentration of 3.08 mM. The enriched AOA, which is provisionally classified as ''Candidatus Nitrososphaera gargensis,'' is the first described thermophilic ammonia oxidizer and the first member of the crenarchaeotal group I.1b for which ammonium oxidation has been verified on a cellular level. Its preference for thermophilic conditions reinvigorates the debate on the thermophilic ancestry of AOA.ammonia oxidation ͉ archaea ͉ nitrification ͉ thermophile ͉ amoA N itrification, the successive microbial oxidation of ammonia via nitrite to nitrate, is a crucial step in the biogeochemical nitrogen cycle, and ammonia-oxidizing microorganisms catalyze the first, rate-limiting step of this process. Until recently, the microbiology of ammonia oxidation was thought to be well understood. Aerobic, chemolithoautotrophic bacteria within the Beta-and Gammaproteobacteria were the only known ammoniaoxidizing microorganisms (1, 2). However, in the last few years, this understanding has been radically changed, first, by the discovery that ammonium can also be oxidized anaerobically by a clade of deep branching planctomycetes (3, 4), and later by the equally surprising cultivation of ammonia-oxidizing archaea (AOA) belonging to the Crenarchaeota (5). Since then, AOA were found to outnumber ammonia-oxidizing bacteria (AOB) in several terrestrial and marine systems, including different soils (6), the North Sea and Atlantic Ocean (7), the Pacific Ocean (8), and the Black Sea (9). Furthermore, molecular analyses demonstrated that AOA also occur in association with marine sponges (10-13), and amoA sequences related to recognized AOA were retrieved in numerous studies from a wide variety of other habitats (7-9, 14-18), including two moderately thermophilic sites with a temperature below 50°C (19,20). The latter findin...

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Aerobic and anaerobic ammonia oxidizing bacteria – competitors or natural partners?

Cited by 46 publications

References 41 publications

Nitrogen biogeochemistry of submarine groundwater discharge

Nitrogen biogeochemistry of submarine groundwater discharge

Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

A moderately thermophilic ammonia-oxidizing crenarchaeote from a hot spring

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