Water in Celtic Countries: Quantity, Quality and Climate Variability (Proceedings of the Fourth InterCeltic Colloquium on Hydrology and Management of Water Resources, Guimarães, Portugal, July 2005). IAHS Publ. 310, 2007, 3-22.
Exchange between systems: from river catchments to
coastal marine waters
J. C. Lefeuvre1 &
E. Feunteun2
1 Muséum National d'Histoire Naturelle,
France
jean-claude.lefeuvre@univ-rennes1.fr
2 University of la Rochelle, Rochelle,
France
Abstract The European Water Framework,
promulgated in 2000, proposed a global approach with a precise schedule and a
clear objective: the long term protection of aquatic environments and resources
and, especially for the rivers, their ecological integrity from the source to the
mouth. For a long time, the “ecosystem approach” appeared a good way in terms
of research to show, at a landscape level, the reality of a link between the
functioning of such different systems as watersheds, rivers, streams, estuaries
and marine coastal water systems. Much research on exchange, transfers of
energy and materials between these systems have proved that, finally, the water
quality in rivers and in the sea as well as and the functioning of aquatic
ecosystems (freshwater and marine ecosystems) depend on the evolution of land
cover and land use of the watersheds. The development of intensive agriculture
that takes no account of the environmental issues, regularly destroys the
integrity of biogeochemical and water transfers between land and ocean. It is
one of the main causes of the disturbance of the functioning of aquatic
ecosystems. In Celtic Countries, at a local scale, the Mont-Saint-Michel bay
and its watershed appears as an appropriate model to analyse the multiple
consequences of land use changes in the watershed, due to agriculture, on the
deterioration of aquatic ecosystem and water quality. Brittany in its entirety
seems to be one of the best models to study the same processes at a regional
scale.
Key
words coastal
marine water; ecosystems; exchange;
freshwater; functions; holistic model; industrial agriculture practice;
landscape; river; transfer; watershed