Some aspects of the phosphorus cycle were studied in the estuarine bay of Marennes, Oléron, an area of intensive cultivation of Crassostrea gigas on the west coast of France. The annual cycle of dissolved phosphorus (mineral and organic) in the water column, interstitial water and at the sediment-water interface was followed, as well as the particulate phosphorus (total and assimilable) in sediments and in suspension. A comparison of the seasonal variations in these different forms of phosphorus in the suspended matters shows a deficit in "biodeposits" (sedimented faeces and pseudofaeces from Crassostrea gigas) equivalent to 20 mg.m -2.d -1 for assimilable phosphorus in July and September-October. This may be the result of consumption by the oysters, since... |