so
R.H. Charlier and Th. Lonhienne
waters. Incidentally occurring toxic blooms are a function of meteorological conditions.
Eutrophication, as stated before, has been reported worldwide and is
more intense in nearly closed basins with a narrow access to the open
sea, such as gulfs, bays and fjords, although it is not necessarily absent
along relatively open coasts. The coastlines and coastal lagoons of Europe are, of course, no exception. Proliferation of algae is a consequence of
this phenomenon (Belkhir 1981; Chassany de Casabianca 1984;
Montgomery et al. 1985; Virnstein and Carbonara 1988).
The eutrophication state of a lagoon can be ascertained by measurements of salinity, temperature, oxygen and nutrients; these measurements will also give information on the existence of anoxic conditions
and stratification.
Nearshore primary producers include phytoplankton, marine phanerogams, benthic micro- and macroalgae. Plant growth is an initial response to
excess nutrients; this may lead to development of the benthic suspensionfeeding bivalves. The initial direct effect of eutrophication is change in
species composition, and next altered distribution patterns such as those of
fucoid algae (Clark 1989; Gray 1991). However, not all algal blooms should
be ascribed to increased nutrients and entrophication. Habitat destruction
probably plays a role. Algal blooms are often sources of toxins or volatile
sulfur compounds; many species are unpalatable to herbivores.
2.3 Eutrophication in European Sea Bodies
Alarming signs of change in nutrient and productivity patterns of ecosystems have been reported for many European coastal waters. They include
increased phytoplankton production and mass development of algae, and
a fortiori green tides (Schramm 1991). The need to protect the systems
from eutrophication and pollution may attract anew attention to marine
macrophytes as candidates for tertiary wastewater treatment; seaweeds are
suited for purification of nitrogen-rich domestic and urban sewage, as well
as for some agricultural and industrial waste eftluents (Schramm 1991).
Proliferation of green algae affects particularly Ulva, Enteromorpha
and Cladophora, and among red algae Gracilaria and Porphyra. Though
proliferation refers mostly to macroalgae and blooms of microalgae, the
ru1e is not absolute. The extent of proliferation has been estimated by
Briand (1987, and in his thesis at Lille in 1989) at 1.3 x 10 6 metric tonnes,
but is probably higher.
R.H. Charlier and Th. Lonhienne
waters. Incidentally occurring toxic blooms are a function of meteorological conditions.
Eutrophication, as stated before, has been reported worldwide and is
more intense in nearly closed basins with a narrow access to the open
sea, such as gulfs, bays and fjords, although it is not necessarily absent
along relatively open coasts. The coastlines and coastal lagoons of Europe are, of course, no exception. Proliferation of algae is a consequence of
this phenomenon (Belkhir 1981; Chassany de Casabianca 1984;
Montgomery et al. 1985; Virnstein and Carbonara 1988).
The eutrophication state of a lagoon can be ascertained by measurements of salinity, temperature, oxygen and nutrients; these measurements will also give information on the existence of anoxic conditions
and stratification.
Nearshore primary producers include phytoplankton, marine phanerogams, benthic micro- and macroalgae. Plant growth is an initial response to
excess nutrients; this may lead to development of the benthic suspensionfeeding bivalves. The initial direct effect of eutrophication is change in
species composition, and next altered distribution patterns such as those of
fucoid algae (Clark 1989; Gray 1991). However, not all algal blooms should
be ascribed to increased nutrients and entrophication. Habitat destruction
probably plays a role. Algal blooms are often sources of toxins or volatile
sulfur compounds; many species are unpalatable to herbivores.
2.3 Eutrophication in European Sea Bodies
Alarming signs of change in nutrient and productivity patterns of ecosystems have been reported for many European coastal waters. They include
increased phytoplankton production and mass development of algae, and
a fortiori green tides (Schramm 1991). The need to protect the systems
from eutrophication and pollution may attract anew attention to marine
macrophytes as candidates for tertiary wastewater treatment; seaweeds are
suited for purification of nitrogen-rich domestic and urban sewage, as well
as for some agricultural and industrial waste eftluents (Schramm 1991).
Proliferation of green algae affects particularly Ulva, Enteromorpha
and Cladophora, and among red algae Gracilaria and Porphyra. Though
proliferation refers mostly to macroalgae and blooms of microalgae, the
ru1e is not absolute. The extent of proliferation has been estimated by
Briand (1987, and in his thesis at Lille in 1989) at 1.3 x 10 6 metric tonnes,
but is probably higher.