The Exchange of Dissolved Substances between Mud and Water in Lakes

Mortimer, C. H.

doi:10.2307/2256691

Cited by 879 publications

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“…1) had extremely high concentrations of iron-bound P (Fe-P) in the surface layer (4 mg kg -1 dw, see further Karlsson et al 2009) indicating an effective trapping of phosphorus. Fe-P is mostly immobile in oxidized sediments but is typically dissolved in the pore water and released to the water column through diffusion if the sediments turn reduced (Mortimer 1941;Balzer 1984;Koop et al 1990;Eilola et al 2009). An interesting question is, therefore, what would happen if the system again deteriorated toward less oxic conditions?…”

Section: Discussionmentioning

confidence: 99%

Indications of Recovery from Hypoxia in the Inner Stockholm Archipelago

Karlsson

Jonsson

Lindgren

et al. 2010

AMBIO

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Improved benthic conditions compared to the 1990s were found during benthic investigations, including sediment and benthic macrofauna in the inner Stockholm archipelago during 2008. In the 1990s, these areas were dominated by black and laminated surface sediments and very sparse fauna. A clear relationship was found when comparing sediment status with the benthic macrofauna. Reduced surface sediment and impoverished macroinvertebrate community was only found at one sampling station representing an enclosed part of the inner archipelago, whereas the other seven stations, with depths ranging from 20 to 50 m, had oxidized surface sediments and considerable biomasses of benthic macrofauna (6-65 g m -2 ) dominated by the invading polychaete Marenzelleria neglecta. An extrapolation of the results shows that, within the investigated area, the coverage of reduced surface sediments had decreased from approximately 17% in the late 1990s to 4% in 2008.

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Section: Discussionmentioning

confidence: 99%

Indications of Recovery from Hypoxia in the Inner Stockholm Archipelago

Karlsson

Jonsson

Lindgren

et al. 2010

AMBIO

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“…Ces variations concernent en premier lieu les nutriments (cf. WETZEL, 1983 ;.GAILU\RD, 1995 ;MlCHARD, 2002), les éléments dont la solubilité est liée aux conditions redox, comme le fer et le manganèse (MORTIMER, 1941 ;DAVISON, 1993 ;HAMILTON-TAYLOR and DAVISON, 1995) et aussi des élé-ments trace comme le cobalt (BALISTRIERI et al, 1992(BALISTRIERI et al, , 1994TAILLEFERT et al, 2002), le baryum (SUGlYAMAef al., 1992 ;VIOLLIER, 1995) ou le vanadium (Viollier efa/.,1995).…”

Section: -Introductionunclassified

Vitesses de réaction de dissolution et précipitation au voisinage de l'interface oxydo-réducteur dans un lac méromictique : le lac Pavin (Puy de Dôme, France)

Michard¹,

Jézéquel²,

Viollier³

2005

rseau

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Une étude à l'échelle centimétrique de l'interface redox situé à la limite entre mixolimnion et monimolimnion d'un lac méromictique (le lac Pavin) a permis d'observer très finement l'évolution de la concentration d'un certain nombre d'éléments chimiques. Nous avons choisi de présenter ici des résultats concernant 5 éléments qui présentent des comportements très contrastés : le rubidium, le fer, le baryum, le vanadium et le manganèse. La comparaison avec un élément conservatif, le sodium, montre que Rb est conservatif, que Fe, Ba et V sont précipités et que Mn est dissous dans cette zone.Une modélisation de ces concentrations en vue de préciser à quelle profondeur et avec quelle vitesse se produisent les réactions concernant ces éléments nécessite la détermination des paramètres de transport au voisinage de cet interface.Une représentation analytique des concentrations de sodium permet de calculer le coefficient de diffusion turbulente Kz en fonction de la profondeur. Au voisinage de l'interface redox, ce coefficient est très petit (0,0017m2/jour) et inférieur au coefficient de diffusion thermique moléculaire.Les concentrations des éléments étudiés ont pu être représentés avec précisions par des polynômes en fonction de la concentration en sodium.Cela permet d'estimer les vitesses des réactions de précipitation dissolution en fonction de la profondeur. Le rubidium n'est affecté par aucune réaction. Le fer précipite entre 63 et 65 m, le baryum entre 68 et 72 m tandis que le vanadium précipite à la fois dans ces 2 zones. Le manganèse réagit dans une zone très étroite : il est précipité entre 61,5 et 62 m et dissous entre 62,8 et 63,1 m.Une étude similaire de tous les éléments majeurs (y compris pH et COD) pourrait permettre d'élucider les processus qui conduisent à ces comportements complexes.Lake Pavin, French Massif Central, is the main meromictic lake in France and has been extensively studied from more than 50 years. The upper part (mixolimnion) at a depth of less than about 60 m behaves as an oligotrophic lake and is oxic during the major part of the year. The lower layer (monimolimnion) has a higher salinity and is permanently anoxic. Unlike the top of the mixolimnion, element concentrations in the monimolimnion can be considered at steady state. The boundary between mixolimnion and monimolimnion is a redox interface. At this interface, an important number of both chemical and biochemical reactions occur. This boundary, where element concentrations vary greatly, was studied at the centimeter scale between 58 and 64 m depth. The present paper is focused on five elements showing very different behaviour: rubidium, iron, manganese, vanadium and barium. Sodium was used as a reference element. Sodium and rubidium concentrations had similar patterns: a progressive increase began at 61 m depth and the maximal gradient was located at 63 m. They continue to increase towards the bottom of the lake. Iron concentrations were low (< 1 µmol/L) at a depth less than 62.8 m and increased very sharply below this depth. Manganes...

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“…360-79) by S. M. Marshall & A. P. Orr (1948) on the effect of different plant nutrients upon the phytoplankton in Loch Craiglin. The deepest water (4-5 m.) was frequently oxygen-free, contained sulphide, and much resembled the freshwater studied by Mortimer (1941) in Esthwaite Water (English Lake District). Such a stratification is likely to lead to the following distribution of iron and phosphate.…”

Section: Addendummentioning

confidence: 64%

“…cf. Mortimer, 1941). Determinations made in the English Channel by the writer in 1933-34 (Cooper, 1935, p. 422) and attributed to ferrous iron now appear to be nothing of the sort.…”

Section: Ferrous Iron In the Sea And In Lakesmentioning

confidence: 99%

Some Chemical Considerations on the Distribution of Iron in the Sea

Cooper

1948

J. Mar. Biol. Ass.

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Three purely chemical topics which have aIisen in the course of the investigation describedin the preceding paper (Cooper, 1948)will be discussed; first, a theoreticaltreatment of the formation and stabilityof ferric phosphate in sea water; secondly,an explanation as to how 2:2'-dipyIidyl may react with ferIic iron at high dilutions in natural waters to give the red ferrous complex; and thirdly, a short account of an expeIiment which showed ferrifiuoIide to be unstablein seawater.. FORMATION AND STABILITY OF FERRIC PHOSPHATE IN SEA WATERTwo seIies of experiments in this laboratory by Harvey (1937) and by the writer (unpublished) on the precipitation of iron from sea water containing phosphate and hydroxyl ions (pH 8'1) do not agree. Sometimesmuch of the phosphate is precipitated, sometimesnone. Much closer control is necessary but it has not been clear what form this should take. The followingtheoretical examination, imperfect though it is, may help in the design of such contro1.Pugh & du Toit (1936)examinedthe ionic exchange or hydrolysis of ferric phosphate and silicate in relatively concentrated systems. Solutions of ferric chloIide were titrated with solutions of phosphate or silicate containing varying amounts of sodium hydroxide. A ferIic phosphate with a higher P04/Fe203 mol-ratio than 0'71 could not be prepared since compounds richer in phosphate hydrolysed until this ratio was reached. There is an optimum value of pH above which the ferIic phosphate hydrolyses further with increasing hydroxyl-ion concentration. The same is true of ferric silicate. At pH 8'0 and above, in presence of hydroxyl, silicateand phosphate in solution, ferric hydroxide would be the stable solid phase. The isoelectric point of ferIic hydroxide prepared from its chloIide is said to be pH 7'1 so that at pH 8'1 ferric hydroxide should be regarded rather as the very sparingly soluble ferrous acid, H3Fe03, which may be expected to dissociate H3Fe03~H+ + H2FeO~. Since FeOH++ is the dominant ferric cation at the isoelectric point, for electroneutrality of the micelle, the concentration of its anion, H2FeO~, should be twice that of its cation, FeOH++. This (Cooper, 1937b, equation 12) will be about 10-}2.54 at 18°C. The solubility product of ferrous acid, (H+) (H2FeO~)will therefore be of the order

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The Exchange of Dissolved Substances between Mud and Water in Lakes

Cited by 879 publications

References 0 publications

Indications of Recovery from Hypoxia in the Inner Stockholm Archipelago

Indications of Recovery from Hypoxia in the Inner Stockholm Archipelago

Vitesses de réaction de dissolution et précipitation au voisinage de l'interface oxydo-réducteur dans un lac méromictique : le lac Pavin (Puy de Dôme, France)

Some Chemical Considerations on the Distribution of Iron in the Sea

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