BioGeoChemistry of Tidal Flats


A. Lübben, T. Badewien, O. Dellwig, S. Koch, S. Koelsch, O. Puncken, R. Reuter

Gelbstoff in the east-frisian wadden sea

Muddy coasts, such as the East-Frisian Wadden Sea, are a typical feature of the south-eastern North Sea. The fundamental physical, chemical and biological interactions characterizing the existence and dynamics of these coastal zones are systematically investigated in the research programme BioGeoChemistry of Tidal flats. Among other water-column parameters, DOM has been the subject of intensive investigations due to its major role for the underwater light climate, for particle aggregation and sedimentation, for trace metal complexation, and many other processes which are relevant for this ecosystem. Its optically active components, denoted as gelbstoff, are photometrically and fluorometrically investigated during ship cruises since 1999, and these data are compared with DOC. The results are surveyed if there are significant variabilities of the optical signatures of gelbstoff in freshwater, sediment porewater, in samples from the backbarrier and open sea water column. Also the influence of seasonal dynamics of biological productivity on the gelbstoff cycle is considered. Furthermore the relations existing between DOC content and optical signatures are studied.