The dissociation of hydrogen sulfide in seawater1

Millero, Frank J.; Plese, Tinka; Fernandez, Marino

doi:10.4319/lo.1988.33.2.0269

Cited by 162 publications

(90 citation statements)

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“…Concentrations of O 2 and S tot were measured by titration (65) and spectrophotometrically (56), respectively. The sulfide concentration in the seawater was calculated using the pK 1 of 6.5, corrected for salinity and temperature (59). The pH was measured with a sulfide-tolerant pH sensor (IntLab 412/170; Mettler Toledo).…”

Section: Methodsmentioning

confidence: 99%

“…The H 2 S concentration in the calibration buffer was calculated using the dissociation constant pK 1 of 6.9, determined as described by Weber (57). The S tot in the sediment layer on the coral was calculated from the H 2 S and pH profile (58) and the pK 1 of 6.6, corrected for temperature and salinity (59). The pH microsensors were calibrated using standard buffers with pH 7.02 and 9.21 (Mettler Toledo) at in situ temperature.…”

Section: Methodsmentioning

confidence: 99%

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Mechanisms of damage to corals exposed to sedimentation

Weber

Beer

Lott

et al. 2012

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

208

139

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We investigated the mechanisms leading to rapid death of corals when exposed to runoff and resuspended sediments, postulating that the killing was microbially mediated. Microsensor measurements were conducted in mesocosm experiments and in naturally accumulated sediment on corals. In organic-rich, but not in organic-poor sediment, pH and oxygen started to decrease as soon as the sediment accumulated on the coral. Organic-rich sediments caused tissue degradation within 1 d, whereas organic-poor sediments had no effect after 6 d. In the harmful organic-rich sediment, hydrogen sulfide concentrations were low initially but increased progressively because of the degradation of coral mucus and dead tissue. Dark incubations of corals showed that separate exposures to darkness, anoxia, and low pH did not cause mortality within 4 d. However, the combination of anoxia and low pH led to colony death within 24 h. When hydrogen sulfide was added after 12 h of anoxia and low pH, colonies died after an additional 3 h. We suggest that sedimentation kills corals through microbial processes triggered by the organic matter in the sediments, namely respiration and presumably fermentation and desulfurylation of products from tissue degradation. First, increased microbial respiration results in reduced O 2 and pH, initiating tissue degradation. Subsequently, the hydrogen sulfide formed by bacterial decomposition of coral tissue and mucus diffuses to the neighboring tissues, accelerating the spread of colony mortality. Our data suggest that the organic enrichment of coastal sediments is a key process in the degradation of coral reefs exposed to terrestrial runoff.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Mechanisms of damage to corals exposed to sedimentation

Weber

Beer

Lott

et al. 2012

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

208

139

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“…The bottom water O 2 concentration was measured by Winkler titration from the same Niskin bottles. Total sulfide was calculated from the local pH and H 2 S concentrations, using a pK value for sulfide of 6.92, as calculated from the local temperature and salinity (Millero et al, 1988). The H 2 S sensors had detection limits for H 2 S of 1 µmol L −1 .…”

Section: Microprofilingmentioning

confidence: 99%

Saturated CO<sub>2</sub> inhibits microbial processes in CO<sub>2</sub>-vented deep-sea sediments

et al. 2013

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Abstract. This study focused on biogeochemical processes and microbial activity in sediments of a natural deep-sea CO2 seepage area (Yonaguni Knoll IV hydrothermal system, Japan). The aim was to assess the influence of the geochemical conditions occurring in highly acidic and CO2 saturated sediments on sulfate reduction (SR) and anaerobic methane oxidation (AOM). Porewater chemistry was investigated from retrieved sediment cores and in situ by microsensor profiling. The sites sampled around a sediment-hosted hydrothermal CO2 vent were very heterogeneous in porewater chemistry, indicating a complex leakage pattern. Near the vents, droplets of liquid CO2 were observed emanating from the sediments, and the pH reached approximately 4.5 in a sediment depth > 6 cm, as determined in situ by microsensors. Methane and sulfate co-occurred in most sediment samples from the vicinity of the vents down to a depth of 3 m. However, SR and AOM were restricted to the upper 7–15 cm below seafloor, although neither temperature, low pH, nor the availability of methane and sulfate could be limiting microbial activity. We argue that the extremely high subsurface concentrations of dissolved CO2 (1000–1700 mM), which disrupt the cellular pH homeostasis, and lead to end-product inhibition. This limits life to the surface sediment horizons above the liquid CO2 phase, where less extreme conditions prevail. Our results may have to be taken into consideration in assessing the consequences of deep-sea CO2 sequestration on benthic element cycling and on the local ecosystem state.

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“…cm-' (9) and was found to be within 5% of the value expected. The reaction H2S --H++ HS-has a pKa of 6.91 at 30°C and infinite dilution (21) [DIC] at the compensation point. The latter two procedures were conducted in the absence and presence of HC03-transport which was initiated by the addition at 25 mM NaCl (6,8,13,20).…”

Section: Preparation Of Na2s and Co2 Stock Solutionsmentioning

confidence: 99%

Selective and Reversible Inhibition of Active CO₂ Transport by Hydrogen Sulfide in a Cyanobacterium

Espie¹,

Miller²,

Canvin³

1989

Plant Physiol.

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The active transport of CO2 in the cyanobacterium Synechococcus UTEX 625 was inhibited by H2S. Treatment of the cells with up to 150 micromolar H2S + HS-at pH 8.0 had little effect on Nat-dependent HC03-transport or photosynthetic O2 evolution, but CO2 transport was inhibited by more than 90%. CO2 transport was restored when H2S was removed by flushing with N2. At constant total H2S + HS-concentrations, inhibition of CO2 transport increased as the ratio of H2S to HS-increased, suggesting a direct role for H2S in the inhibitory process. Hydrogen sulfide does not appear to serve as a substrate for transport. In the presence of H2S and Na -dependent HC03-transport, the extracellular CO2 concentration rose considerably above its equilibrium level, but was maintained far below its equilibrium level in the absence of H2S. The inhibition of CO2 transport, therefore, revealed an ongoing leakage from the cells of CO2 which was derived from the intracellular dehydration of HC03-which itself had been recently transported into the cells. Normally, leaked CO2 is efficiently transported back into the cell by the CO2 transport system, thus maintaining the extracellular CO2 concentration near zero. It is suggested that CO2 transport not only serves as a primary means of inorganic carbon acquisition for photosynthesis but also serves as a means of recovering CO2 lost from the cell. A schematic model describing the relationship between the CO2 and HCO3-transport systems is presented. 8,13,20) and Anabaena variabilis ( 11) MATERIALS AND METHODS Organisms and GrowthThe unicellular cyanobacterium Synechococcus leopoliensis UTEX 625 (University of Texas Culture Collection, Austin, TX) was grown with air-bubbling (0.05% v/v CO2) in unbuffered Allen's medium at 30°C as described previously (6). Experimental ConditionsCells were washed three times by centrifugation (1 min at l0,OOOg, Beckman microfuge B) and resuspended (7-9 sg Chl * mL-') in 25 mm BTP/HC1 buffer of the appropriate pH.The buffer contained about 15 uM DIC and 5 Mm Na+ as contaminants. Washed cells (6 mL) were subsequently placed in a thermostated (30°C) glass reaction vessel (20 mm diameter) and briefly purged with a stream of N2 to reduce the [02] to less than 75 AM. The chamber was then closed to the atmosphere and the cells were allowed to temperature equilibrate for several minutes in darkness. The reaction vessel contained a port for the inlet capillary of a mass spectrometer and the cell suspension was continuously stirred with a magnetic stirrer during measurements. Light was provided by a 387 www.plantphysiol.org on May 10, 2018 -Published by Downloaded from

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The dissociation of hydrogen sulfide in seawater1

Abstract: Abstract-The pK,* for the dissociation of H,S has been measured in artificial seawater as a function of salinity (S = 5-40)

Cited by 162 publications

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Mechanisms of damage to corals exposed to sedimentation

Mechanisms of damage to corals exposed to sedimentation

Saturated CO<sub>2</sub> inhibits microbial processes in CO<sub>2</sub>-vented deep-sea sediments

Selective and Reversible Inhibition of Active CO₂ Transport by Hydrogen Sulfide in a Cyanobacterium

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The dissociation of hydrogen sulfide in seawater1

Abstract: Abstract-The pK,* for the dissociation of H,S has been measured in artificial seawater as a function of salinity (S = 5-40)

Cited by 162 publications

References 0 publications

Mechanisms of damage to corals exposed to sedimentation

Mechanisms of damage to corals exposed to sedimentation

Saturated CO&lt;sub&gt;2&lt;/sub&gt; inhibits microbial processes in CO&lt;sub&gt;2&lt;/sub&gt;-vented deep-sea sediments

Selective and Reversible Inhibition of Active CO2 Transport by Hydrogen Sulfide in a Cyanobacterium

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Saturated CO<sub>2</sub> inhibits microbial processes in CO<sub>2</sub>-vented deep-sea sediments

Selective and Reversible Inhibition of Active CO₂ Transport by Hydrogen Sulfide in a Cyanobacterium