HYDROGRAPHY AND PHYTOPLANKTON BIOMASS IN THE EASTERN ENGLISH-CHANNEL IN SPRING 1992

The coastal water in the Eastern English Channel, named 'fleuve cotier ' (FC) between the River Seine and the Cape Gris-Nez, is a low-salinit y water mass because of the integrated continental runoffs. This coast al water is often limited seaward by coastal front(s) and is character ized as a transfer pathway from the English Channel to the North Sea. The results of this study show that the phytoplankton production start is located off the Seine: and Somme Estuaries, and the phytoplanktoni c production is lower in the deep and turbulent waters off the Pays-de -Caux, in spite of their nutrient richness. The dispersion of the near shore produced biomass is often seaward-limited by the coastal front. Nevertheless, the system is complex and the overall biomass distributi on is nor. always limited by the front because production exists offsh ore of the front. The production seems limited by the depth (20-25 m) independently of the FC structure. In fact, the FC itself appears neit her sufficient nor indispensable to develop the phytoplanktonic produc tion in the Eastern English Channel. The broad Picardy Bay, including a pan of FC and offshore water, is revealed as an isolated phytoplankt onic system. (C) 1996 Academic Press Limited