Mathematical models for estimating fluxes at the sediment-water interface in benthic chamber experiments

Maran, Stefano; Ciceri, G.; Martinotti, W.

doi:10.1007/bf00033503

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…Por otra parte, los flujos calculados a partir de los perfiles verticales sólo tienen en cuenta procesos difusivos, no considerando otros efectos, como la resuspensión debida a corrientes o la irrigación de la macrofauna bentónica (Ciceri et al, 1992;Maran et al, 1995). Estos errores podrían subsanarse con la medida de los flujos mediante cámaras bentónicas.…”

Section: Discussionunclassified

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Influence of anthropogenic activity on the vertical distribution of Zn, Cd, Pb and Cu in interstitial water and coastal marine sediments (Cádiz bay, SW Spain)

Ponce¹,

Forja²,

Gómez-Parra³

2000

Cienc. Mar.

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Recibido en junio de 1999; aceptado en mayo de 2000 RESUMENSe han determinado los perfiles verticales de concentración de Zn, Cd, Pb y Cu en el sedimento y el agua intersticial de tres estaciones de la Bahía de Cádiz. Las concentraciones de los distintos metales encontradas en los sedimentos superficiales dependen de su distancia a los puntos de vertido de los efluentes residuales existentes en la zona y de la naturaleza de éstos (urbana o industrial). Así, los niveles más elevados de Pb y Cd (70 y 0.31 µg g -1 , respectivamente) se han hallado en las inmediaciones de vertidos urbanos, y los de Zn y Cu (230 y 106 µg g -1 , respectivamente) en las proximidades de industrias relacionadas con la construcción naval. Los perfiles verticales de Zn, Cd, Pb y Cu, tanto en sedimento como en agua intersticial, muestran un notable aumento de la concentración en las capas más superficiales y unas concentraciones relativamente constantes a partir de los 20 cm. Las concentraciones en el agua intersticial son sensiblemente menores que las medidas en el sedimento, variando entre 13 y 57 µg L -1 para el Zn, entre 3 y 11 µg L -1 para el Pb, entre 9 y 320 µg L -1 para el Cu y entre 0.07 y 2.4µgL -1 para elCd. Los valores obtenidos para el índice de geoacumulación propuesto por Müller (1979) permiten considerar a la zona estudiada en una situación intermedia entre un sistema no contaminado y de contaminación moderada. Los valores encontrados para el factor de enriquecimiento superficial (concentración en los 5 cm superficiales/niveles basales) para los cuatro metales en las distintas estaciones, sugieren un único origen de contaminación por metales en la zona.Palabras clave: metales pesados, sedimentos costeros, agua intersticial, contaminación, voltoamperometría de redisolución anódica.http://dx.doi.org/10. 7773/cm.v26i3.590 Ciencias Marinas, Vol. 26, No. 3, 2000 480 INTRODUCCIÓNEl comportamiento de los metales pesados constituye uno de los tópicos más estudiados en el medio marino, debido principalmente a su persistencia en el medio y a sus efectos sobre la biota. En general, estos elementos presentan una elevada capacidad para adsorberse sobre el material particulado (Brzezinska et al., 1984;Salomons et al., 1987;Dai et al., 1995;Wood et al., 1995), lo que hace que su destino principal sea la incorporación a los sedimentos costeros (de Groot et al., 1976). Este comportamiento está bien establecido para un gran número de metales, cuyos coeficientes de reparto entre la fase sólida y el agua presentan valores típicos comprendidos entre 10 3 y 10 4 (Bryan y Gibbs, 1983;Bryan, 1985; Bryan y Langston, 1992). Una vez que los metales son incorporados al sedimento, el cambio en las condiciones redox del medio provocado por la diagéne-sisinicial de la materia orgánica afecta al tipoy a la intensidad de la interacción entre metal y la fase sólida, lo que origina, en

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Section: Discussionunclassified

“…On the other hand, the fluxes calculated from the vertical profiles only consider diffuse processes and not other effects, such as resuspension due to currents or the irrigation of the benthic macrofauna (Ciceri et al, 1992;Maran et al, 1995). These errors could be rectified with the measurement of the fluxes with benthic chambers.…”

Section: Flujos Difusivosmentioning

confidence: 99%

Influence of anthropogenic activity on the vertical distribution of Zn, Cd, Pb and Cu in interstitial water and coastal marine sediments (Cádiz bay, SW Spain)

Ponce¹,

Forja²,

Gómez-Parra³

2000

Cienc. Mar.

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“…The rate of solute transport across the sedimentwater interface is often important when determining a nutrient budget for a water body or investigating the fate of a contaminant (Jorgensen & Revsbech 1985, Maran et al 1995. The solute transport across the interface is affected by biological and chemical processes within the sediments, as well as by the benthic hydrodynamics.…”

Section: Introductionmentioning

confidence: 99%

Estimation of a characteristic friction velocity in stirred benthic chambers

Oldham

Ivey

Pullin³

2004

Mar. Ecol. Prog. Ser.

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The ecology of water bodies can be greatly affected by the flux of solutes across the sediment -water interface. This solute flux is frequently measured using either benthic chambers in the field or incubated sediment cores, where in both cases the sediment is removed from the influence of the natural hydrodynamics. To compensate, the overlying water is usually stirred in some manner, e.g. with a rotating impeller, in an attempt to reproduce the natural field conditions. The hydrodynamics affect the diffusive-boundary-layer thickness, which can be one of the major controls on solute flux magnitude. Thus, a quantitative understanding of the effects of chamber stirring is vital. In this paper a characteristic friction velocity is presented as a function of a given stirrer configuration and stirring rate. The developed scaling relationship correlates well (R 2 ≈ 0.9) with previously reported friction velocities in benthic chambers, over a range of chamber configurations and sizes. It is now possible, using this equation for characteristic friction velocities, to ensure that benthic chambers experience similar turbulence intensities to natural environments, without elaborate turbulence measurements.

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“…Thus, Hall et al (1989) describe a l-dimensional tra.nsport-reaction model to calculate the oxygen uptake by sediments in long-duration (7 wk) incubation experiments. More recently, Maran et al (1995) proposed 2 mathematical models for the quantification of the benthic fluxes of various metals in incubations of 15 d duration. These modelling exercises took into account some of the processes affecting the concentration of trace elements in the benthic chamber, mainly the process of advective transport due to the sedimentation of suspended matter and sorption/desorption between the solid and liquid phases.…”

Section: Introductionmentioning

confidence: 99%

Measuring nutrient fluxes across the sediment-water interface using benthic chambers

Forja¹,

Gómez-Parra²

1998

Mar. Ecol. Prog. Ser.

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This paper presents a simple model to determine the benthic fluxes of matter across the sediment-water Interface when a benth~c chamber is used. The model is based on accepting that the limiting step for the overall rate of transfer while the chamber is in position is the diffusion through the diffusive boundary layer (DBL) overlying the sediment, and it assumes that this rate is necessarily affected by the procedure employed to measure the flux. Alteration of the benthic fluxes due to the actlon of macrofauna is included in the model and, operatively, is expressed in terms of a reduction in the thickness of the DBL between the sediment and the water. If the diffusive fluxes are determined simultaneously w~t h the benthic chamber experiments, a value can be estimated for the thickness of the 'stagnant film'. Owing to the assumptions made and to the micro-heterogeneities of the sediment, this thickness can be considered to have both an operative and a statistical meaning, with respect to the entire surface area covered by the chamber. The values calculated in the Bay of Cadiz (SW Spain) vary between 0.36 and 0.71 nun, w h~c h are in agreement w~t h measurements of this film made by different techniques in other littoral ecosystems. However, the values of the in situ fluxes estimated using this model and by other established procedures described in the literature can differ by more than SO%, for the same experiment, in strongly irrigated zones.

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Mathematical models for estimating fluxes at the sediment-water interface in benthic chamber experiments

Cited by 7 publications

References 15 publications

Influence of anthropogenic activity on the vertical distribution of Zn, Cd, Pb and Cu in interstitial water and coastal marine sediments (Cádiz bay, SW Spain)

Influence of anthropogenic activity on the vertical distribution of Zn, Cd, Pb and Cu in interstitial water and coastal marine sediments (Cádiz bay, SW Spain)

Estimation of a characteristic friction velocity in stirred benthic chambers

Measuring nutrient fluxes across the sediment-water interface using benthic chambers

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