Precise shipboard determination of dissolved oxygen (Winkler procedure) for productivity studies with a commercial system1

Oudot, Claude; Gerard, Robert; Morin, Pascal; Gningue, Itaf

doi:10.4319/lo.1988.33.1.0146

Cited by 156 publications

(110 citation statements)

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“…Oxygen concentrations were analysed by Winkler titration using a potentiometric electrode and automated endpoint detection (Mettler Toledo, DL28 titrator) (Oudot et al, 1988). CR and NCP were calculated from changes in dissolved oxygen concentration after incubation of samples under "dark" and "light" conditions, respectively and GPP was calculated by solving the mass balance equation GPP=NCP−CR.…”

Section: Methodsmentioning

confidence: 99%

Patterns in planktonic metabolism in the Mediterranean Sea

2009

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Abstract. Planktonic gross community production (GPP), net community production (NCP) and community respiration (CR) across the Mediterranean Sea was examined in two cruises, THRESHOLDS 2006 and 2007, each crossing the Mediterranean from West to East to test for consistent variation along this longitudinal gradient in late spring to early summer. GPP averaged 2.4±0.4 mmol O 2 m −3 d −1 , CR averaged 3.8±0.5 mmol O 2 m −3 d −1 , and NCP averaged -0.8±0.6 mmol O 2 m −3 d −1 across the studied sections, indicative of a tendency for a net heterotrophic metabolism in late spring to early summer, prevalent across studied sections of the Mediterranean Sea as reflected in 70% of negative NCP estimates. The median P /R ratio was 0.6, also indicating a strong prevalence of heterotrophic communities (P /R<1) along the studied sections of the Mediterranean Sea. The communities tended to be net heterotrophic (i.e. P /R<1) at GPP less than 2.8 mmol O 2 m −3 d −1 . The Western Mediterranean tended to support a higher gross primary production and community respiration than the Eastern basin did, but these differences were not statistically significant (ttest, p > 0.05). The net heterotrophy of the studied sections of the Mediterranean Sea indicates that allochthonous carbon should be important to subsidise planktonic metabolism during the late spring.

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Section: Methodsmentioning

confidence: 99%

Patterns in planktonic metabolism in the Mediterranean Sea

2009

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“…Gross production rates were calculated from the increased oxygen concentration after incubation of samples in the light relative to those incubated in the dark. Dissolved oxygen concentration was measured using high-precision Winkler titration after Carrit & Carpenter (1966), using a Metrohm-682 Autotritator for the potentiometric (redox electrode) end-point detection (Oudot et al 1988). The average coefficient of variation of the dissolved oxygen concentration was about 0.35% and the resulting detection limit for net production and respiration was about 0.0009 mg O 2 l -1 h -1 .…”

Section: Methodsmentioning

confidence: 99%

Experimental induction of a large phytoplankton bloom in Antarctic coastal waters

Agustı́¹,

Duarte²

2000

Mar. Ecol. Prog. Ser.

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The experimental enclosure of an Antarctic planktonic community in a large (35 m 3 ) mesocosm moored in Johnson's Dock (62°39.576' S, 60°22.408' W, Livingston Island, Bransfield Sector, Antarctica) was followed by a large phytoplankton bloom. This bloom, dominated by the large diatom Thalassiosira antarctica, reached a biomass 1000-fold greater than in the ambient waters. The net growth rate of T. antarctica averaged 0.53 ± 0.17 d -1 , with maximum net growth rates close to 1.0 d -1 , exceeding the predicted maximal population growth rates by 60 to 200%. The gross primary production in the mesocosm (49 mmol C m -3 d -1 ) was about 30 times greater than the concurrent gross production in the ambient waters, while sedimentation losses removed only between 2.1 to 13% of the biomass d -1 and cell mortality was negligible. The bloom development led to a decline of dissolved inorganic nutrient concentrations to values several times lower than those in the ambient waters, indicating that the ambient nutrients were both available and sufficient to allow the development of the massive algal bloom observed. Light-limitation of the phytoplankton community was likely the factor responsible for the low biomass and production in ambient waters relative to the mesocosm, as indicated by: (1) limited water transparency of about 1 m, which increased up to 6 m as a result of the sedimentation of the glacial flour in the mesocosm; (2) dense pigment packaging (14.7 ± 3 pg chl a µm -3 ) inside the phytoplankton cells of the community in the ambient waters compared to much lower values (4.2 ± 0.8 pg chl a µm -3 ) in the mesocosm community; (3) a specific light absorption of the phytoplankton community in the ambient waters 10 times higher (average specific PAR absorption ± SE = 0.018 ± 0.0038 m -1 mg chl a -1 ) than in the mesocosm community (0.0087 ± 0.002 m -2 mg -1 chl a); and (4)

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“…Community metabolism (gross primary production, community respiration and net community production) was determined from changes in oxygen over a 24 h period using the micro-Winkler method for determining dissolved oxygen concentration (Oudot et al, 1988). During the experiment with the open-ocean Arctic community, metabolic rates were determined on days 3, 4, 8, and 15 of the experimental period.…”

Section: Variables Measuredmentioning

confidence: 99%

“…Dark bottles were wrapped in black electrical tape and incubated in a submerged black plastic bag, while light bottles were incubated in submerged transparent plastic bags. Oxygen concentrations were analyzed by Winkler titration using a potentiometric electrode and automated endpoint detection (Mettler Toledo, DL28 titrator) following Oudot et al (1988). Community respiration (CR) and net community production (NCP) were calculated by subtracting initial dissolved oxygen concentrations from dissolved oxygen concentrations measured after incubation in the dark and light conditions respectively.…”

Section: Variables Measuredmentioning

confidence: 99%

Experimentally determined temperature thresholds for Arctic plankton community metabolism

et al. 2013

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Abstract. Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 • C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rates and thus both the rate of primary production and respiration will increase. However, these predictions do not consider the specific metabolic balance of the communities. We tested, experimentally, the response of Arctic plankton communities to seawater temperature spanning from 1 • C to 10 • C. Two types of communities were tested, open-ocean Arctic communities from water collected in the Barents Sea and Atlantic influenced fjord communities from water collected in the Svalbard fjord system. Metabolic rates did indeed increase as suggested by metabolic theory, however these results suggest an experimental temperature threshold of 5 • C, beyond which the metabolism of plankton communities shifts from autotrophic to heterotrophic. This threshold is also validated by field measurements across a range of temperatures which suggested a temperature 5.4 • C beyond which Arctic plankton communities switch to heterotrophy. Barents Sea communities showed a much clearer threshold response to temperature manipulations than fjord communities.

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Precise shipboard determination of dissolved oxygen (Winkler procedure) for productivity studies with a commercial system1

Cited by 156 publications

References 0 publications

Patterns in planktonic metabolism in the Mediterranean Sea

Patterns in planktonic metabolism in the Mediterranean Sea

Experimental induction of a large phytoplankton bloom in Antarctic coastal waters

Experimentally determined temperature thresholds for Arctic plankton community metabolism

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