Description:There is an intuitive belief among scientists that each estuary or lagoon is unique and different. Similarities do exist, however, and this book attempts to highlight some common properties and perhaps some innovative views on biogeochemical processes, and biological fluxes which are of central concern in the understanding of the land-sea boundary. The contents are based upon lectures given at a Seminar organised as the scientific component of the 17th General Meeting of SCOR, held at the Station Biologique de Roscoff, France, on 22-24 October 1984. The original lectures have been substantially extended and revised in order to give a fuller treatment of the subject. The contributions identify important processes influencing (I) Behaviour of chemical species, (II) Nutrient cycling and mechanisms of organic transformations and (III) Uptake of trace elements by living systems. The connection between terrestrial and oceanic systems is a functional one and the consequences of this linkage on the very large variety of coastal systems are profound.