Active nitrogen-fixing heterotrophic bacteria at and below the chemocline of the central Baltic Sea

Farnelid, Hanna; Bentzon-Tilia, Mikkel; Andersson, Anders F.; Bertilsson, Stefan; Jost, Günter; Labrenz, Matthias; Jürgens, Klaus; Riemann, Lasse

doi:10.1038/ismej.2013.26

Cited by 136 publications

(163 citation statements)

References 57 publications

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“…In ammonium-rich environments such as the DHAB interfaces and brines (Daffonchio et al, 2006), dinitrogen fixation is expected to be inhibited (Madigan et al, 2008), but some organisms are capable of maintaining high N 2 fixation rates in the presence of a high level of ammonium. This was observed in isolates (Okoronkwo et al, 1989) and in natural populations from deep anoxic waters of the Baltic Sea (Farnelid et al, 2013). The binning of nitrogenase transcripts from the LI were to Archaea, including methanogens and ANME.…”

Section: Metabolism Of Nitrogen Compoundsmentioning

confidence: 69%

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

et al. 2014

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Deep-sea hypersaline anoxic basins (DHABs) in the Eastern Mediterranean Sea are considered some of the most hostile environments on Earth. Little is known about the biochemical adaptations of microorganisms living in these habitats. This first metatranscriptome analysis of DHAB samples provides significant insights into shifts in metabolic activities of microorganisms as physicochemical conditions change from deep Mediterranean sea water to brine. The analysis of Thetis DHAB interface indicates that sulfate reduction occurs in both the upper (7.0-16.3% salinity) and lower (21.4-27.6%) halocline, but that expression of dissimilatory sulfate reductase is reduced in the more hypersaline lower halocline. High dark-carbon assimilation rates in the upper interface coincided with high abundance of transcripts for ribulose 1,5-bisphosphate carboxylase affiliated to sulfuroxidizing bacteria. In the lower interface, increased expression of genes associated with methane metabolism and osmoregulation is noted. In addition, in this layer, nitrogenase transcripts affiliated to uncultivated putative methanotrophic archaea were detected, implying nitrogen fixation in this anoxic habitat, and providing evidence of linked carbon, nitrogen and sulfur cycles.

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Section: Metabolism Of Nitrogen Compoundsmentioning

confidence: 69%

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

et al. 2014

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“…Because OMZs account for up to 50% of oceanic N 2 production, they have the potential to limit primary production in overlying surface waters (7,8). A recent model suggests that nitrogen fixation in proximity to OMZ waters can balance nitrogen loss processes (9), and several studies along redoxclines in the Eastern Tropical South Pacific and Baltic Sea have measured nitrogen fixation rates that support a close spatial coupling between nitrogen loss and nitrogen fixation consistent with this model (10)(11)(12). Moreover, recent studies have begun to link the oxidation of reduced sulfur-compounds including thiosulfate (S 2 O 3 2-) and hydrogen sulfide (H 2 S) to nitrogen transformations in nonsulfidic OMZs, providing evidence for a cryptic sulfur cycle with the potential to drive inorganic carbon fixation processes (13).…”

mentioning

confidence: 64%

Metaproteomics reveals differential modes of metabolic coupling among ubiquitous oxygen minimum zone microbes

Hawley¹,

Brewer

Norbeck

et al. 2014

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

162

193

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Marine oxygen minimum zones (OMZs) are intrinsic water column features arising from respiratory oxygen demand during organic matter degradation in stratified waters. Currently OMZs are expanding due to global climate change with resulting feedback on marine ecosystem function. Here we use metaproteomics to chart spatial and temporal patterns of gene expression along defined redox gradients in a seasonally stratified fjord to better understand microbial community responses to OMZ expansion. The expression of metabolic pathway components for nitrification, anaerobic ammonium oxidation (anammox), denitrification, and inorganic carbon fixation were differentially expressed across the redoxcline and covaried with distribution patterns of ubiquitous OMZ microbes including Thaumarchaeota, Nitrospina, Nitrospira, Planctomycetes, and SUP05/ARCTIC96BD-19 Gammaproteobacteria. Nitrification and inorganic carbon fixation pathways affiliated with Thaumarchaeota dominated dysoxic waters, and denitrification, sulfur oxidation, and inorganic carbon fixation pathways affiliated with the SUP05 group of nitrate-reducing sulfur oxidizers dominated suboxic and anoxic waters. Nitrifier nitrite oxidation and anammox pathways affiliated with Nirospina, Nitrospira, and Planctomycetes, respectively, also exhibited redox partitioning between dysoxic and suboxic waters. The numerical abundance of SUP05 proteins mediating inorganic carbon fixation under anoxic conditions suggests that SUP05 will become increasingly important in global ocean carbon and nutrient cycling as OMZs expand.M arine oxygen (O 2 ) minimum zones (OMZs) are widespread and naturally occurring water column features that arise when respiratory O 2 demand during decomposition of organic matter exceeds O 2 availability in stratified waters. Operationally defined by dissolved O 2 concentrations <20 μM, OMZs promote the use of alternative terminal electron acceptors (TEAs) in microbial energy metabolism that results in climate active gas production including carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ) (1). Currently, OMZs constitute ∼7% of the ocean volume (1, 2). However, global warming promotes conditions for OMZ expansion and intensification, e.g., reduced O 2 solubility and increased stratification, with resulting feedback on the climate system (3, 4).Within OMZs, the use of nitrate (NO 3 − ) and nitrite (NO 2 − ) as TEAs in dissimilatory nitrate reduction (denitrification) and anaerobic ammonium oxidation (anammox) results in fixed nitrogen loss in the form of N 2 O and dinitrogen gas (N 2 ), respectively (5, 6). Because OMZs account for up to 50% of oceanic N 2 production, they have the potential to limit primary production in overlying surface waters (7,8). A recent model suggests that nitrogen fixation in proximity to OMZ waters can balance nitrogen loss processes (9), and several studies along redoxclines in the Eastern Tropical South Pacific and Baltic Sea have measured nitrogen fixation rates that support a close spatial coupling between nitro...

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“…Also, the diazotrophic community may be dominated by heterotrophic bacteria (Farnelid et al, 2011(Farnelid et al, , 2013Moisander et al, 2014;Bentzon-Tilia et al, 2015). In this study, significant N 2 and N 2 O fixation rates were determined in surface waters and in ice brine during the same expedition cruise.…”

Section: Pml and Haloclinementioning

confidence: 87%

Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean)

Verdugo

Damm

Snoeijs

et al. 2016

Deep Sea Research Part I: Oceanographic Research Papers

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A B S T R A C TThe concentration of greenhouse gases, including nitrous oxide (N 2 O), methane (CH 4 ), and compounds such as total dimethylsulfoniopropionate (DMSP t ), along with other oceanographic variables were measured in the icecovered Arctic Ocean within the Eurasian Basin (EAB). The EAB is affected by the perennial ice-pack and has seasonal microalgal blooms, which in turn may stimulate microbes involved in trace gas cycling. Data collection was carried out on board the LOMROG III cruise during the boreal summer of 2012. Water samples were collected from the surface to the bottom layer (reaching 4300 m depth) along a South-North transect (SNT), from 82.19°N, 8.75°E to 89.26°N, 58.84°W, crossing the EAB through the Nansen and Amundsen Basins. The Polar Mixed Layer and halocline waters along the SNT showed a heterogeneous distribution of N 2 O, CH 4 and DMSP t , fluctuating between 42-111 and 27-649% saturation for N 2 O and CH 4, respectively; and from 3.5 to 58.9 nmol L −1 for DMSP t . Spatial patterns revealed that while CH 4 and DMSP t peaked in the Nansen Basin, N 2 O was higher in the Amundsen Basin. In the Atlantic Intermediate Water and Arctic Deep Water N 2 O and CH 4 distributions were also heterogeneous with saturations between 52% and 106% and 28% and 340%, respectively. Remarkably, the Amundsen Basin contained less CH 4 than the Nansen Basin and while both basins were mostly under-saturated in N 2 O. We propose that part of the CH 4 and N 2 O may be microbiologically consumed via methanotrophy, denitrification, or even diazotrophy, as intermediate and deep waters move throughout EAB associated with the overturning water mass circulation. This study contributes to baseline information on gas distribution in a region that is increasingly subject to rapid environmental changes, and that has an important role on global ocean circulation and climate regulation.

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Active nitrogen-fixing heterotrophic bacteria at and below the chemocline of the central Baltic Sea

Cited by 136 publications

References 57 publications

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

Metaproteomics reveals differential modes of metabolic coupling among ubiquitous oxygen minimum zone microbes

Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean)

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