Biogenic silica dissolution in seawater — in vitro chemical kinetics

Greenwood, Jim; Truesdale, Victor W.; Rendell, A.R.

doi:10.1016/s0079-6611(00)00046-x

Cited by 61 publications

(60 citation statements)

References 46 publications

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“…Hence, dissolution of bSi from diatoms dispersed in the SSW could quantitatively explain the increase in concentration. However, following the linear initial rate approach (Greenwood et al 2001), a bSi dissolution rate of 0.12 d -1 was obtained for POM at 8.5°C. This rate is 3 times higher than previously found in studies that were conducted at temperatures 5 or 10°C higher than the present study (Bidle & Azam 2001, Moriceau et al 2007).…”

Section: Degradation Of Particulate Matter In Aggregatesmentioning

confidence: 99%

Effects of rising temperature on the formation and microbial degradation of marine diatom aggregates

Piontek¹,

Händel²,

Langer³

et al. 2009

Aquat. Microb. Ecol.

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Section: Degradation Of Particulate Matter In Aggregatesmentioning

confidence: 99%

Effects of rising temperature on the formation and microbial degradation of marine diatom aggregates

Piontek¹,

Händel²,

Langer³

et al. 2009

Aquat. Microb. Ecol.

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“…We used the linear initial rate approach described in the comparative study of Greenwood et al (2001). The initial specific bSiO 2 dissolution rate (R, in nmol Si s -1 g bSiO 2 -1 or in % d -1…”

Section: Dry Weightmentioning

confidence: 99%

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Moriceau¹,

Garvey²,

Ragueneau³

et al. 2007

Mar. Ecol. Prog. Ser.

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International audienceBecause aggregated diatoms sink rapidly through the water column, leaving little time for dissolution, aggregation influences the balance between recycling of biogenic silica (bSiO2) and its sedimentation and preservation at the seafloor. Additionally, aggregation may directly impact dissolution rates of opal. Laboratory experiments were conducted to investigate the influence of aggregation on bSiO2 dissolution rates using 3 different batch cultures of the diatoms Chaetoceros decipiens, Skeletonema costatum, and Thalassiosira weissflogii. Specific dissolution rates of bSiO2 of aggregated and freely suspended diatoms were compared. Additionally, the influences of the dissolved silicon (dSi) concentration in the pore water of aggregates, the viability of diatoms, and the concentrations of transparent exopolymer particles (TEP) and of bacteria on bSiO2 dissolution rates were determined. Initial specific dissolution rates of diatom frustules were significantly lower for aggregated diatoms (2.9% d–1) than for freely suspended diatoms (6.6% d–1). Lower specific dissolution rates in aggregates were attributed to elevated dSi concentrations in aggregate pore water (maximum 230 vs. 20 µmol l–1) and to the fact that aggregated diatoms remained viable for longer than freely suspended diatoms. Specific bSiO2 dissolution was significantly correlated to viability of cells independent of treatment. Bacterial concentrations in both treatments appeared high enough, so that after cell death the coating protecting the silica frustule was degraded without measurable delay. The TEP content of aggregates appeared to affect dissolution rates, possibly by retaining solutes within aggregates

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“…Going further, Rickert et al (2002) proposed a kinetics of higher order to account for nonlinear aspects of BSi dissolution kinetics. Asymptotic Si concentrations are commonly assumed to represent the equilibrium solubility or saturation concentration, but they rarely if ever reach the solubility of acid-cleaned BSi (e.g., Berelson et al, 1987;Van Cappellen and Qiu, 1997a;Rabouille et al, 1997) which needs to be considered when interpreting the results of in vitro studies where acid cleaning often is the standard procedure (Barker et al, 1994;Van Cappellen and Qiu, 1997b;Greenwood et al, 2001). Additionally, asymptotic concentrations and kinetic constants both show considerable variations even on a local scale, and among sediments of similar ecosystem composition regarding silicic organisms (Schink et al, 1975;Archer et al, 1993;McManus et al, 1995;Van Cappellen and Qiu, 1997a,b).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the lack of mechanistic understanding of the processes that control the local kinetic rate constant (k) and the local saturation concentration (C ∞ ), early diagenetic sediment models use these as fitting parameters. Consequently, the predictive power of diagnostic silica dissolution models is limited, and models validated for a specific problem tend to fail when applied to different sites (McManus et al, 1995;Greenwood et al, 2001). From laboratory studies, the temperature, pH, undersaturation, and electrolyte composition of the aqueous medium, as well as the specific surface area, impurity content, and aging of BSi have already been identi-fied as system variables of BSi solubility and dissolution kinetics (Lewin, 1961;Van Cappellen and Qiu, 1997a,b;Dixit et al, 2001;Van Cappellen, 2002, 2003;Rickert et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…From laboratory studies, the temperature, pH, undersaturation, and electrolyte composition of the aqueous medium, as well as the specific surface area, impurity content, and aging of BSi have already been identi-fied as system variables of BSi solubility and dissolution kinetics (Lewin, 1961;Van Cappellen and Qiu, 1997a,b;Dixit et al, 2001;Van Cappellen, 2002, 2003;Rickert et al, 2002). Consequently, the array of proposed mechanisms extends from diffusive transport through a boundary layer, or a solid layer leached by preferential dissolution (transport limitation), to decreasing surface area due to dissolution, formation of coatings, adsorbtion of inhibitors, or precipitation of authigenic silicates (surface chemistry limitation) (Ragueneau et al, 2000;Greenwood et al, 2001). For instance, a conclusive empirical relation in field and in vitro data exists between asymptotic Si concentration and the detrital to opal ratio in surface sediments, suggesting a significant lowering of BSi solubility by aluminum released from lithogenic mineral phases (Van Bennekom et al, 1991;Van Cappellen and Qiu, 1997a;Dixit and Van Cappellen, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Microbial mediation of benthic biogenic silica dissolution

Holstein

Hensen

2009

Geo-Mar Lett

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Pore water profiles from 24 stations in the South Atlantic (located in the Guinea, Angola, Cape, Guyana, and Argentine basins) show good correlations of oxygen and silicon, suggesting microbially mediated dissolution of biogenic silica. We used simple analytical transport and reaction models to show the tight coupling of the reconstructed process kinetics of aerobic respiration and silicon regeneration. A generic transport and reaction model successfully reproduced the majority of Si pore water profiles from aerobic respiration rates, confirming that the dissolution of biogenic silica (BSi) occurs proportionally to O 2 consumption. Possibly limited to well-oxygenated sediments poor in BSi, benthic Si fluxes can be inferred from O 2 uptake with satisfactory accuracy. Compared to aerobic respiration kinetics, the solubility of BSi emerged as a less influential parameter for silicon regeneration. Understanding the role of bacteria for silicon regeneration requires further investigations, some of which are outlined. The proposed aerobic respiration control of benthic silicon cycling is suitable for benthic-pelagic models. The empirical relation of BSi dissolution to aerobic respiration can be used for regionalization assessments and estimates of the silicon budget to increase the understanding of global primary and export production patterns.

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Biogenic silica dissolution in seawater — in vitro chemical kinetics

Cited by 61 publications

References 46 publications

Effects of rising temperature on the formation and microbial degradation of marine diatom aggregates

Effects of rising temperature on the formation and microbial degradation of marine diatom aggregates

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Microbial mediation of benthic biogenic silica dissolution

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