No abstract

Bioassays have been carried out with the green algae Scenedesmus crassus on samples of soft sediments collected along the river Lot (about fifty samples distributed over a 300 km length) in order to evaluate the phosphate bioavailability. From an other study, it was possible to know the percent of bottom surface covered by soft sediments . The link between the distribution of soft sediment and phosphate bioavailability leads to a longitudinal representation of the storage in the whole river . The results point out the parts of the river where bioavailable phosphate is stored and have implications for possible role of the stored phosphate in the eutrophication process in some areas of the river Lot .