Hydrocarbons in the water column of the carteau bay (gulf of fos-sur-mer,mediterranean sea)

The distribution of hydrocarbons in the water column seems to be affected by inputs from both interfaces of accumulation: the surface microlayer and the water/sediment interface. Volatilization and accommodation appear to be the major factors controlling the fate of hydrocarbons, especially in the dissolved phase, whereas some classes of particles are confirmed as important supports for the transport of such pollutants. In this respect, the 20–200 μm planktonic fraction is less contaminated than the total suspended matter.This study gives evidence for intense bacterial degradation affecting the hydrocarbons in the whole water column. In spite of the chronic petroleum pollution, we have also observed the predominance of n-alkanes in the n-C16; n-C18] and n-C27, n-C29] boiling ranges, which could be used as biological markers in these highly polluted waters.