Nitrification rates, ammonium and nitrate distribution in upper layers of the water column and in sediments of the Indian sector of the Southern Ocean

Bianchi, Micheline; Feliatra, F.; Tréguer, Paul; Vincendeau, Marie-Anne; Morvan, J.

doi:10.1016/s0967-0645(96)00109-9

Cited by 110 publications

(108 citation statements)

References 26 publications

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“…2, Table 1). These rates are within the range of rates reported for different coastal waters (40-3000 nmol N L −1 h −1 ) (overview in de Bie et al, 2002). Nitrification may have been stimulated by the continuous aeration of the bottles, which was necessary to prevent settling of the particulate material and possible associated reduction of oxygen concentrations.…”

Section: Nitrification Ratessupporting

confidence: 81%

“…4). The 13 C-labeled PLFA profile is similar to the profile from a comparable experiment in the Scheldt Estuary (de Bie et al, 2002) and is consistent with 16:0, 16:1ω7c and 18:1ω7c Table 2. Inhibition of 13 C-DIC fixation in PLFAs and crenarchaeol by nitrapyrin and chlorate.…”

Section: Activity Of Autotrophic Nitrifying Bacteriasupporting

confidence: 78%

“…Containers were placed in a temperature-controlled room at in situ temperature and water was aerated to keep particulate material in suspension and the water oxygenated. One of the containers received 5 mg L −1 of nitrapyrin, an inhibitor of ammonium oxidation also known as N-Serve (Brion and Billen, 1998;de Bie et al, 2002), and one received 10 mM of sodium chlorate, an inhibitor of nitrite oxidation (Belser and Mays, 1980). All four containers were left to settle in darkness for about 2 h. Thereafter, 4 mmol 13 C-bicarbonate (NaH 2 CO 3 , 99 % 13 C) was added to the two containers with and one without inhibitors, resulting in a concentration of 200 µM, which corresponded to ±10 % of ambient DIC concentrations.…”

Section: C-dic Incubationsmentioning

confidence: 99%

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Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

et al. 2013

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Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with ¹⁵N-ammonium and growth of autotrophic nitrifiers was measured by incubation with ¹³C-DIC (dissolved inorganic carbon) in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) in combination with compound-specific stable isotope (¹³C) analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N L⁻¹ h⁻¹). Ammonium assimilation was always substantially lower than nitrification – with nitrification on average contributing 89% (range 73–97%) to total ammonium consumption.

¹³C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95 %). The inhibitor-sensitive ¹³C-PLFA (phospholipid-derived fatty acid) pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. ¹³C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase)). These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance measurements only, in order to elucidate their biogeochemical importance. The ratio between rates of nitrification versus DIC fixation by bacterial nitrifiers was higher or even much higher than typical values for autotrophic nitrifiers, indicating that little DIC was fixed relative to the amount of energy that was generated by nitrification

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Section: Nitrification Ratessupporting

confidence: 81%

Section: Activity Of Autotrophic Nitrifying Bacteriasupporting

confidence: 78%

Section: C-dic Incubationsmentioning

confidence: 99%

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Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

et al. 2013

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“…However, we note that urea uptake, a proxy for dissolved organic N assimilation, is usually relatively low south of the polar front, where dissolved inorganic N is abundant (Waldron et al, 1995;Sambrotto and Mace, 2000;Savoye et al, 2004). (Lipschultz et al, 1991;Ward, 2008) and above the one reported for the Southern Ocean (< 0.1 µmol L −1 d −1 ; Olson, 1981;Bianchi et al, 1997). The Southern Ocean nitrification data available in the literature pertain to autumn and winter, seasons during which primary production and remineralization are expected to be low.…”

Section: Upper-ocean N Cycling: High F Ratios and Nitrification Ratesmentioning

confidence: 93%

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

et al. 2015

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Abstract. Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO − 3 and NH + 4 ), and nitrification rates were measured at eight stations in austral spring 2011 (October-November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m −2 d −1 and up to 0.31 d −1 respectively) compared to the HNLC reference site (12 mmol C m −2 d −1 and 0.06 d −1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO − 3 -uptake / (NO − 3 -uptake + NH + 4 -uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ∼ 3 µmol N L −1 d −1 , with ∼ 90 % of them < 1 µmol N L −1 d −1 ) typically occurring below the euphotic zone, as classically observed in the global ocean. The specificity of the studied area is that at most of the stations, the euphotic layer was shallower than the mixed layer, implying that nitrifiers can efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.

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“…Their chemical processes, i.e. nitrification or denitrification, occur as the phenomena that affects bacteria and phytoplankton (Bianchi et al 1994;Bianchi et al 1995;Ward et al 1989). This has subsequently become known as the phenomena correlated to the biological pump (Herndl & Reinthaler, 2013, Jiao & Zheng, 2011Sanders et al 2014;Tortell et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Organic Matter and Nutrient Profile of the Two-Current-Regulated-Zone in the Southwestern Sumatran Waters (Ssw)

Wahyudi

Iskandar²,

Meirinawati³

et al. 2017

Mar. Res. Indonesia

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The Indian Ocean is influenced by monsoon systems which alter the ocean's physical and chemical properties. Specifically, the southwestern Sumatran waters in the eastern Indian Ocean are considered a dual current regulated zone i.e. affected by South Equatorial Counter Current (SECC) and South Java Current (SJC). This area is considered as having an important role in the transfer of organic matter or the biological pump. However, the information about this area is minimal, especially in terms of organic matter and nutrient profile. This study will update the recent information about the area, including the profile of particulate organic matter (POM), macro-nutrients, total suspended solids (TSS), macromolecule-degrading bacteria, and soft bottom macrobenthic organisms sampled from 26 stations in both the SECC-regulated zone and the SJC-regulated zone. The physical profile is typical of tropical waters and both zones have a distinct profile of organic matter and nutrients. The particulate organic carbon (POC), particulate organic nitrogen (PON), and TSS of the SECC-regulated zone can be considered higher than those of the SJC-regulated zone. This region is categorized as mesotrophic waters, especially from the surface up to 100 m. The production of nutrients and organic matter in the water column in this area contribute significantly to the abundance of heterotrophic bacteria and benthic organisms.

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Nitrification rates, ammonium and nitrate distribution in upper layers of the water column and in sediments of the Indian sector of the Southern Ocean

Cited by 110 publications

References 26 publications

Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

Organic Matter and Nutrient Profile of the Two-Current-Regulated-Zone in the Southwestern Sumatran Waters (Ssw)

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