Coulometric total carbon dioxide analysis for marine studies: maximizing the performance of an automated gas extraction system and coulometric detector

Johnson, K.M.; Wills, K.D.; Butler, Dan; Johnson, William K.; Wong, C. S.

doi:10.1016/0304-4203(93)90201-x

Cited by 346 publications

(208 citation statements)

References 11 publications

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“…CO 2 fixation rates were derived (see Supplementary Information) from the fraction of 14 C incorporated in relation to the total activity added and the background concentration of dissolved inorganic carbon ranging between 2003 and 2037 mmol kg À 1 (Gotland Deep, July 2011). The determination of C T was performed by coulometry using the SOMMA system designed by Johnson et al (1993). The system was calibrated with certified carbon reference material (Dr A Dickson, University of California, San Diego, La Jolla, CA, USA) and allowed for a precision/accuracy of approximately ±2 mmol kg À 1 .…”

Section: Dark Co 2 Fixationmentioning

confidence: 99%

Significance of archaeal nitrification in hypoxic waters of the Baltic Sea

et al. 2014

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Ammonia-oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread, and their abundance in many terrestrial and aquatic ecosystems suggests a prominent role in nitrification. AOA also occur in high numbers in oxygen-deficient marine environments, such as the pelagic redox gradients of the central Baltic Sea; however, data on archaeal nitrification rates are scarce and little is known about the factors, for example sulfide, that regulate nitrification in this system. In the present work, we assessed the contribution of AOA to ammonia oxidation rates in Baltic deep basins and elucidated the impact of sulfide on this process. Rate measurements with 15 N-labeled ammonium, CO 2 dark fixation measurements and quantification of AOA by catalyzed reporter deposition-fluorescence in situ hybridization revealed that among the three investigated sites the highest potential nitrification rates (122-884 nmol l À 1 per day) were measured within gradients of decreasing oxygen, where thaumarchaeotal abundance was maximal (2.5-6.9 Â 10 5 cells per ml) and CO 2 fixation elevated. In the presence of the archaeal-specific inhibitor GC 7 , nitrification was reduced by 86-100%, confirming the assumed dominance of AOA in this process. In samples spiked with sulfide at concentrations similar to those of in situ conditions, nitrification activity was inhibited but persisted at reduced rates. This result together with the substantial nitrification potential detected in sulfidic waters suggests the tolerance of AOA to periodic mixing of anoxic and sulfidic waters. It begs the question of whether the globally distributed Thaumarchaeota respond similarly in other stratified water columns or whether the observed robustness against sulfide is a specific feature of the thaumarchaeotal subcluster present in the Baltic Deeps.

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Section: Dark Co 2 Fixationmentioning

confidence: 99%

Significance of archaeal nitrification in hypoxic waters of the Baltic Sea

et al. 2014

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“…[9] Dissolved inorganic carbon was determined by coulometric titration [DOE, 1994] with a SOMMA instrument [Johnson et al, 1993] fit to a UIC 5011 coulometer and calibrated against certified standards (CRM Batch 61, provided by Andrew Dickson of the Scripps Institute of Oceanography) and a secondary standard which was regularly calibrated directly against CRM Batch 61. Precision, Figure 1.…”

Section: Dicmentioning

confidence: 99%

Vertical stability and the annual dynamics of nutrients and chlorophyll fluorescence in the coastal, southeast Beaufort Sea

et al. 2008

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[1] The first quasi-annual time series of nutrients and chlorophyll fluorescence in the southeast Beaufort Sea showed that mixing, whether driven by wind, local convection, or brine rejection, and the ensuing replenishment of nutrients at the surface were minimal during autumn and winter. Anomalously high inventories of nutrients were observed briefly in late December, coinciding with the passage of an eddy generated offshore. The concentrations of NO 3 À in the upper mixed layer were otherwise low and increased slowly from January to April. The coincident decline of NO 2 À suggested nitrification near the surface. The vernal drawdown of NO 3 À in 2004 began at the ice-water interface during May, leaving as little as 0.9 mM of NO 3 À when the ice broke up. A subsurface chlorophyll maximum (SCM) developed promptly and deepened with the nitracline until early August. The diatom-dominated SCM possibly mediated half of the seasonal NO 3 À consumption while generating the primary NO 2 À maximum. Dissolved inorganic carbon and soluble reactive phosphorus above the SCM continued to decline after NO 3 À was depleted, indicating that net community production (NCP) exceeded NO 3 À -based new production. These dynamics contrast with those of productive Arctic waters where nutrient replenishment in the upper euphotic zone is extensive and NCP is fueled primarily by allochthonous NO 3 À . The projected increase in the supply of heat and freshwater to the Arctic should bolster vertical stability, further reduce NO 3 À -based new production, and increase the relative contribution of the SCM. This trend might be reversed locally or regionally by the physical forcing events that episodically deliver nutrients to the upper euphotic zone.

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“…Calculations of C assimilation were made taking into account the added radiolabeled bicarbonate and the total amount of dissolved inorganic C (DIC) in the samples. DIC content was determined by coulometric determination (Johnson et al, 1993) with calibration against certified reference material provided by A. Dickson (Scripps Institution of Oceanography).…”

Section: Bulk Uptake Of Bicarbonatementioning

confidence: 99%

High bicarbonate assimilation in the dark by Arctic bacteria

et al. 2010

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Although both autotrophic and heterotrophic microorganisms incorporate CO 2 in the dark through different metabolic pathways, this process has usually been disregarded in oxic marine environments. We studied the significance and mediators of dark bicarbonate assimilation in dilution cultures inoculated with winter Arctic seawater. At stationary phase, bicarbonate incorporation rates were high (0.5-2.5 lg C L À1 d À1 ) and correlated with rates of bacterial heterotrophic production, suggesting that most of the incorporation was due to heterotrophs. Accordingly, very few typically chemoautotrophic bacteria were detected by 16S rRNA gene cloning. The genetic analysis of the biotin carboxylase gene accC putatively involved in archaeal CO 2 fixation did not yield any archaeal sequence, but amplified a variety of bacterial carboxylases involved in fatty acids biosynthesis, anaplerotic pathways and leucine catabolism. Gammaproteobacteria dominated the seawater cultures (40-70% of cell counts), followed by Betaproteobacteria and Flavobacteria as shown by catalyzed reporter deposition fluorescence in situ hybridization (CARDFISH). Both Beta-and Gammaproteobacteria were active in leucine and bicarbonate uptake, while Flavobacteria did not take up bicarbonate, as measured by microautoradiography combined with CARDFISH. Within Gammaproteobacteria, Pseudoalteromonas-Colwellia and Oleispira were very active in bicarbonate uptake (ca. 30 and 70% of active cells, respectively), while the group Arctic96B-16 did not take up bicarbonate. Our results suggest that, potentially, the incorporation of CO 2 can be relevant for the metabolism of specific Arctic heterotrophic phylotypes, promoting the maintenance of their cell activity and/or longer survival under resource depleted conditions.

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Coulometric total carbon dioxide analysis for marine studies: maximizing the performance of an automated gas extraction system and coulometric detector

Cited by 346 publications

References 11 publications

Significance of archaeal nitrification in hypoxic waters of the Baltic Sea

Significance of archaeal nitrification in hypoxic waters of the Baltic Sea

Vertical stability and the annual dynamics of nutrients and chlorophyll fluorescence in the coastal, southeast Beaufort Sea

High bicarbonate assimilation in the dark by Arctic bacteria

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