The principal aim of the project is to establish a link between the marine carbon and sulphur cycles, for which the marine phytoplankton taxon Phaeocystis sp. was chosen as a model organism. This colony forming alga is an important source of the volatile organic sulphur compound dimethyl sulphide (DMS), and its dense blooms can act as a carbon sink. By combining the expertise of researchers working on the carbon and sulphur cycles a thorough inventory of these chemicals will be made. This should result in a better understanding of the role of Phaeocystis blooms in the escape of DMS in the atmosphere and of carbon from the photic zone, and consequently of its role in climate control.