Organic matter composition and pollutant enrichment of sea surface microlayer inside and outside slicks

• Published in: Marine environmental research 1993-01, Vol.35 (4), p.323-339
• Main Authors: Garabetian, Frédéric, Romano, Jean-Claude, Paul, Raoul, Sigoillot, Jean-Claude
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/0141-1136(93)90100-E

Surface microlayer samples were collected with a rotating device at eight stations in a coastal area, and examined, with their related bulk waters, for their organic matter composition. At each station, sampling operations were conducted inside and outside slicks. With the exception of pigments, all the examined groups of compounds, particularly hydrocarbons and anionic detergents, exhibit accumulation in surface microlayer; enrichment is higher in samples collected inside slicks than outside. A decrease of the surface tension measurements is linked to the accumulation of organic matter in the slicks. In surface microlayers, the major part of the identified organic fraction, consists of carbohydrates and proteinaceous compounds rather than lipids. As far as could be deduced from an estimation of lipid, sugar- and protein-carbon, half the recorded particulate organic carbon weight is of an unidentified complex form. The study of hydrolysis kinetics of the carbohydrate particulate fraction shows that the organic matter is in a less condensed form in surface microlayers than in bulk water samples. A close relationship appears between pollutant accumulation and the lowering of surface tension in slicks. This has a direct consequence: the dampening effect on waves which smooths the surface of the sea, making slicks observable features of pollutant accumulation.