Éléments azotés de la colonne d'eau et de l'interface eau-sédiment du bassin de Marennes-Oléron : influence des cultures d'huîtres

Feuillet-Girard, Michelle; Héral, Maurice; Sornin, Jean-Marc; Deslous-Paoli, Jean-Marc; Robert, Jean‐Michel; Mornet, Françoise; Razet, Daniel

doi:10.1051/alr:1988025

Cited by 20 publications

(16 citation statements)

References 13 publications

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“…Conversely, in winter, organic matter degradation is low while TPN s~lpply is high, leading to sediment enrichment in particulate organic matter. The level of organic matter (nitrogen, PAN) is clearly higher in sediments below oysters (Kusuki 1981, Sornin et al 1983, Feuillet-Girard et al 1988). In the pond studied here, the sediment richness under oysters was due to particulate organic supplies by sedimentation plus supplies by biodeposition which can increase the deposited quantities by a factor of 20 (Sornin et al 1987).…”

Section: Discussionmentioning

confidence: 94%

Nitrogenous nutrient transfers in oyster ponds: role of sediment in deferred primary production

Sornin¹,

Collos²,

Delmas³

et al. 1990

Mar. Ecol. Prog. Ser.

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The oyster pond under study has a natural sediment bottom and water is changed only once or twice every month depending on tidal height. Between successive water renewals, the pond is a closed system, equivalent to a batch culture in which sinking and biodeposition of particulate matter are the only sources of organic matter to the bottom. Particulate organic matter enrichment of the sediment in winter is followed by intensive ammonification in summer with very limited nitrification. Seasonal nitrogen budgets involving particulate and dissolved phases show that in summer during batch mode periods, ammonium enrichment from the sediment to the overlying water is an order of magnitude higher than the initial nutrient supply in the feed water. This allows a large increase of the phytoplankton biomass. We introduce the term 'deferred' primary production for this phenomenon because of the seasonal lag between particulate nitrogen deposition and dissolved nitrogen fluxes from the sediment. INTRODUCTIONIn coastal and estuarine areas, benthic organic matter mineralization and exchanges at the waterhediment interface are important processes in nutrient cycling (Nixon 1981, Balzer 1984, Hopkinson 1987. Moreover, there is now evidence that benthic nutrient flux contributes significantly to the requirements of pelagic primary producers (Boynton & Kemp 1985, Hargrave & Phillips 1986.Along the French Atlantic coast, shallow oyster ponds (less than 1 m deep) cover several thousand hectares in marsh areas. These ponds are subjected to high nutrient pulses from feed water at spring tides. As a result of their physical characteristics (small volume, well-defined water exchanges between pond and sea), their large planktonic blooms and easy access, these ponds can be used as models to study biological rate processes.Early studies of seasonal variations in phytoplankton abundance in such environments (Zanette 1980) showed maximal biomass during summer, when the nutrient supply by feed water was lowest. Similar observations were made by Robert (1983) who also reported a decrease in external nutrient supply and an increase in chlorophyll a values during summer.In the present study, seasonal variations of various elements in suspended matter, as well as exchanges between water and sediment, were followed in an oyster pond in order to determine if nutrient regeneration in sediments during summer allows the development of a phytoplankton biomass which cannot be explained by the initial nutrient supply. Conversely, we also determined if, during winter, the supply of organic matter to the sediment would allow sufficient accumulation of nitrogen reserves.Since shellfish cultures enrich the sediment through biodeposition processes (Kusuki 1981, Sornin et al. 1983) and enhance the recycling of some elements to the overlying water (Kaspar et al. 1985), we made these measurements in an oyster culture sediment area with high sedimentation rate and high organic matter content, and compared these to a control sediment area without oyster ...

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Section: Discussionmentioning

confidence: 94%

Nitrogenous nutrient transfers in oyster ponds: role of sediment in deferred primary production

Sornin¹,

Collos²,

Delmas³

et al. 1990

Mar. Ecol. Prog. Ser.

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“…Ammonia accumulation in pore water and/or enhanced nitritication might account for the apparent deficit of nitrogen release in the water column. Oyster bed pore water is known to accumulate ammonia, as well as nitrate, during the summer, in relation with high excretory activity of the invertebrates (Lerat et al, 1985 ;Feuillet-Girard et al, 1988). Oysters are nitrate flux increasers (Henriksen et al, 1983).…”

Section: Discussionmentioning

confidence: 99%

In situ study of the effect of oyster biomass on benthic metabolic exchange rates

Boucher-Rodoni

Boucher

1990

Hydrobiologia

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Oxygen consumption and dissolved nitrogen fluxes at the water-sediment interface of an oyster-bed were measured in situ using transparent enclosures inserted on undisturbed sediment. Experiments were performed in summer, under dark and light conditions, with various densities of the oyster Crassostrea gigas (O-150 animals m -'). The influence of oyster biomass on oxygen and ammonia exchange rates was similar in both lighting conditions. Oxygen consumption increased with increasing biomass, though not at the level of prediction for the highest biomasses, suggesting a depressed respiration rate. Ammonia release never matched the rates predicted by adding sediment efllux to oyster excretion, when biomass exceeded 100 g DW m -*. The coupling between oxygen consumption and ammonia release (0 : N ratio) was thus influenced by oyster biomass. Stabilization of nitrogen release was related to enhanced nitritication in the presence of oyster and/or sediment uptake of ammonia against the molecular gradient. Urea release was erratic but appeared uninfluenced by oyster biomass. Fluxes of oxygen and of each nitrogen compound displayed thus a specific response to modifications of the oyster biomass. Both the organisms and the sediment are involved in regulation processes of metabolic exchange rates at the water-sediment interface.

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“…Particle uptake and release as pseudo-faeces only slightly alters the particle composition, so that particles remain available to the other components of the ecosystem (Feuillet-Girard et al 1994). The released fraction of consumed energy comprises between 62 and 92% , 1992, Soletchnick et al 1996, of which 50 to 90% are pseudo-faeces (Deslous-Paoli et al 1992, Soletchnik et al 1993).…”

Section: Methodological Choicesmentioning

confidence: 99%

“…However, these particles can enrich benthic exchanges in comparison to the pelagic ones. Pseudofaeces production by oysters has been evaluated in Feuillet-Girard et al (1994). An inverse analysis computed with this data showed that an inclusion of the pseudo-faeces production obscures most of the other processes.…”

Section: Methodological Choicesmentioning

confidence: 99%

Numerical analysis of the food web of an intertidal mudflat ecosystem on the Atlantic coast of France

Leguerrier¹,

Niquil²,

Boileau³

et al. 2003

Mar. Ecol. Prog. Ser.

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Éléments azotés de la colonne d'eau et de l'interface eau-sédiment du bassin de Marennes-Oléron : influence des cultures d'huîtres

Abstract: Éléments azotés de la colonne d'eau et de Pinterfacf': eau-sédim.ent du bassin de Marennes-Oléron c influence des culttuOes d'huître.':.

Cited by 20 publications

References 13 publications

Nitrogenous nutrient transfers in oyster ponds: role of sediment in deferred primary production

Nitrogenous nutrient transfers in oyster ponds: role of sediment in deferred primary production

In situ study of the effect of oyster biomass on benthic metabolic exchange rates

Numerical analysis of the food web of an intertidal mudflat ecosystem on the Atlantic coast of France

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