The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen

Sigman, Daniel M.; DiFiore, Peter J.; Hain, Mathis P.; Deutsch, Curtis; Wang, Yi; Karl, David M.; Knapp, Angela N.; Lehmann, Moritz F.; Pantoja, Silvio

doi:10.1016/j.dsr.2009.04.007

Cited by 196 publications

(280 citation statements)

References 53 publications

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“…1C and Dataset S1). The δ 15 N and δ 18 O values of deep nitrate were similar to previously reported data in other oceanic regions (19). The temperature and salinity profiles suggest the presence of at least five types of water masses throughout the depth profile: surface water (above 50 mbs), high salinity water (∼150 mbs), low salinity water (∼400 mbs), mesopelagic water (above 2,000 mbs), and deep water (below 2,000 mbs) (Fig.…”

Section: Resultssupporting

confidence: 78%

“…Water samples were taken in a total of three dives of the remotely operated vehicle (ROV) ABISMO at the same station (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22).25′N, 142-42.75′E) on the Challenger Deep. The temperature and salinity profiles were Significance Although many microbial explorations for hadal sediments began in the 1950s, the hadal water is the least-explored microbial biosphere.…”

Section: Resultsmentioning

confidence: 99%

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Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth

Nunoura

Takaki

Hirai

et al. 2015

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

244

314

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Hadal oceans at water depths below 6,000 m are the least-explored aquatic biosphere. The Challenger Deep, located in the western equatorial Pacific, with a water depth of ∼11 km, is the deepest ocean on Earth. Microbial communities associated with waters from the sea surface to the trench bottom (0 ∼10,257 m) in the Challenger Deep were analyzed, and unprecedented trench microbial communities were identified in the hadal waters (6,000 ∼10,257 m) that were distinct from the abyssal microbial communities. The potentially chemolithotrophic populations were less abundant in the hadal water than those in the upper abyssal waters. The emerging members of chemolithotrophic nitrifiers in the hadal water that likely adapt to the higher flux of electron donors were also different from those in the abyssal waters that adapt to the lower flux of electron donors. Species-level niche separation in most of the dominant taxa was also found between the hadal and abyssal microbial communities. Considering the geomorphology and the isolated hydrotopographical nature of the Mariana Trench, we hypothesized that the distinct hadal microbial ecosystem was driven by the endogenous recycling of organic matter in the hadal waters associated with the trench geomorphology.hadal | trench | niche separation | nitrification | Challenger Deep

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth

Nunoura

Takaki

Hirai

et al. 2015

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

244

314

View full text Add to dashboard Cite

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“…2b). In contrast, ocean-wide δ 15 NO − 3 averages are near 5 and 2 ‰, respectively (Sigman et al, 2009). At our other Peru OMZ stations, maximal δ 15 NO − 3 is typically ∼ 15 ‰ and values as high as 24 ‰ have been reported from other OMZ's (Altabet et al, 1999).…”

Section: An N-loss Hotspotmentioning

confidence: 99%

“…Dissimilatory NO − 3 reduction to NO − 2 is known to produce both strong N as well as O isotopic fractionation (Granger et al, 2008) (Casciotti and McIlvin, 2007; fractionation factor, ε ∼ 25 ‰). Presumably because 15 N-depleted N 2 gas is ultimately produced via preferential loss of 14 N, this process is responsible for enriching the oceanic fixed-N inventory in 15 N (δ 15 N ∼ 5 ‰ relative to atmospheric N 2 ; Sigman et al, 2009) as compared to sources (e.g. −1 to −2 ‰ for N 2 fixation; Carpenter et al, 1997).…”

Section: A Altabet Et Al: An Eddy-stimulated Hotspot For Fixed Nmentioning

confidence: 99%

An eddy-stimulated hotspot for fixed nitrogen-loss from the Peru oxygen minimum zone

et al. 2012

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Abstract. Fixed nitrogen (N) loss to biogenic N 2 in intense oceanic O 2 minimum zones (OMZ) accounts for a large fraction of the global N sink and is an essential control on the ocean's N-budget. However, major uncertainties exist regarding microbial pathways as well as net impact on the magnitude of N-loss and the ocean's overall N-budget. Here we report the discovery of a N-loss hotspot in the Peru OMZ associated with a coastally trapped mesoscale eddy that is marked by an extreme N-deficit matched by biogenic N 2 production, high NO − 2 levels, and the highest isotope enrichments observed so far in OMZ's for the residual NO − 3 . High sea surface chlorophyll in seaward flowing streamers provides evidence for offshore eddy transport of highly productive, inshore water. Resulting pulses in the downward flux of particles likely stimulated heterotrophic dissimilatory NO − 3 reduction and subsequent production of biogenic N 2 within the OMZ. A shallower biogenic N 2 maximum within the oxycline is likely a feature advected by the eddy streamer from the shelf. Eddy-associated temporal-spatial heterogeneity of N-loss, mediated by a local succession of microbial processes, may explain inconsistencies observed among prior studies. Similar transient enhancements of N-loss likely occur within all other major OMZ's exerting a major influence on global ocean N and N isotope budgets.

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“…Nitrification is also the main determinant in setting the average d 18 O of marine NO 3 À (Casciotti et al, 2002;Sigman et al, 2009) and N 2 O (Ostrom et al, 2000;Popp et al, 2002). Determining the oxygen isotope effects for archaeal ammonia oxidation will therefore be an important next step in advancing the use of the dual isotope signatures of NO 3 À and N 2 O to understand the marine nitrogen cycle.…”

Section: Nitrogen Isotopic Fractionationmentioning

confidence: 99%

Enrichment and characterization of ammonia-oxidizing archaea from the open ocean: phylogeny, physiology and stable isotope fractionation

2011

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Archaeal genes for ammonia oxidation are widespread in the marine environment, but direct physiological evidence for ammonia oxidation by marine archaea is limited. We report the enrichment and characterization of three strains of pelagic ammonia-oxidizing archaea (AOA) from the North Pacific Ocean that have been maintained in laboratory culture for over 3 years. Phylogenetic analyses indicate the three strains belong to a previously identified clade of water column-associated AOA and possess 16S ribosomal RNA genes and ammonia monooxygenase subunit a (amoA) genes highly similar (98-99% identity) to those recovered in DNA and complementary DNA clone libraries from the open ocean. The strains grow in natural seawaterbased liquid medium while stoichiometrically converting ammonia (NH 3 ) to nitrite (NO 2 À ). Ammonia oxidation by the enrichments is only partially inhibited by allylthiourea at concentrations known to completely inhibit cultivated ammonia-oxidizing bacteria. The three strains were used to determine the nitrogen stable isotope effect ( 15 e NH3 ) during archaeal ammonia oxidation, an important parameter for interpreting stable isotope ratios in the environment. Archaeal 15 e NH3 ranged from 13% to 41%, within the range of that previously reported for ammonia-oxidizing bacteria. Despite low amino acid identity between the archaeal and bacterial Amo proteins, their functional diversity as captured by 15 e NH3 is similar.

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The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen

Cited by 196 publications

References 53 publications

Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth

Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth

An eddy-stimulated hotspot for fixed nitrogen-loss from the Peru oxygen minimum zone

Enrichment and characterization of ammonia-oxidizing archaea from the open ocean: phylogeny, physiology and stable isotope fractionation

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