Climate Change and the European Water Dimension - Agri ...

IV.D.1. Introduction
Coastal lagoons are inland water bodies separated from the Sea by littoral arrows
and sand barriers connected by one or more inlets. They have shallow waters, few
meters depth, and a salinity that varies from fresh water to hypersaline depending on
their water balance (Kjerfve, 1994). River mouths can play a crucial role in lagoon
formation with their sediment contribution. Morpho-dynamics of tidal lagoons is
controlled by long-term (net) sediment fluxes between littoral and tidal channels as
well as between channels and shallows (intertidal shoals and salt marshes). Coastal
lagoons are common along the Atlantic and Mediterranean coasts of Southern
Europe, as well as along the south-eastern Baltic coast. Several fjords along the
Danish coast can be considered to some extent as lagoons, as they have restricted
mouths and slow water exchange with the Baltic Sea. In many coastal areas,
especially in Netherlands, lagoons have decreased or almost disappeared as a
consequence of land reclamation and coastal protection programmes. Mediterranean
coastal lagoons are microtidal or non tidal, whilst along the Atlantic coast they are
mesotidal (de Wit et al., 2001). Coastal lagoons play a key role as spawning grounds
for fish and shellfish, see Figures IV.D.1-2; for this reason, such areas are also
extensively exploited for aquaculture, especially for mollusc farming. Moreover, they
are often important for bird reproduction and rest areas, and they present a rich and
specific biodiversity, both for fauna and flora.
Figure IV.D.1: Ria Formosa-Clam culture (bivalve hand collection, 5000 tons/y)
(Photo courtesy of Dr. Falcao, IPIMAR, Portugal)
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