The Management of Eutrophicated Waters
49
NUTRIENT SOURCES
---I WEATHER CONDITIONS
I EUTROPHICATION
I HYDRODYNAMICS
1
1
BIOLOGICAL PROCESSES
I EXCEPTIONAL BLOOMS
Fig. 2.2. Major factors leading to algal blooms
like M. Aubert (1990) have held for some time that such an explanation
is too "simplistic" in view of the complexity of the natural phenomena.
In his "theory on eutrophication", the processes are enhanced by
mediators secreted by specific biota that condition relations between
marine organisms. Ecological disorders ensue when pollutants that alter
the activities of mediators disrupt the normal phytoplanktonic cycle.
Eutrophication and dystrophication then occur.
"Exceptional blooms" designate algal proliferation that have harmful
effects for man. Blooms may be punctual (single occurrence) or recurrent. They are linked to biological processes influenced by three parameters (Fig. 2.2): (1) eutrophication; (2) hydrodynamics; and (3)
weather conditions, which also have an impact on the two other
parameters. Hydrodynamic parameters include currents, water temperature and salinity, tides and the position of the thermal and haline picnolines. Weather conditions influence nutrients' presence, hydrodynamics
and biological processes through air temperature, isolation precipitation,
speed and direction of winds.
Exceptional blooms depend upon complex biological processes, at the
level of the first trophic system in the ecosystem. They include photosynthesis and growth of the plankton, interspecies competition, predatory
behavior of zooplankton, molluscs and crustaceans, algal sedimentation,
and bacterial decomposition. The so-called Lake of Tunis, for example, is
the site of extreme eutrophication during the summer months, where, in
calm weather, the whole water column may become anaerobic. Nitrite
concentrations may reach 50 times those of enclosed bays in Greek
49
NUTRIENT SOURCES
---I WEATHER CONDITIONS
I EUTROPHICATION
I HYDRODYNAMICS
1
1
BIOLOGICAL PROCESSES
I EXCEPTIONAL BLOOMS
Fig. 2.2. Major factors leading to algal blooms
like M. Aubert (1990) have held for some time that such an explanation
is too "simplistic" in view of the complexity of the natural phenomena.
In his "theory on eutrophication", the processes are enhanced by
mediators secreted by specific biota that condition relations between
marine organisms. Ecological disorders ensue when pollutants that alter
the activities of mediators disrupt the normal phytoplanktonic cycle.
Eutrophication and dystrophication then occur.
"Exceptional blooms" designate algal proliferation that have harmful
effects for man. Blooms may be punctual (single occurrence) or recurrent. They are linked to biological processes influenced by three parameters (Fig. 2.2): (1) eutrophication; (2) hydrodynamics; and (3)
weather conditions, which also have an impact on the two other
parameters. Hydrodynamic parameters include currents, water temperature and salinity, tides and the position of the thermal and haline picnolines. Weather conditions influence nutrients' presence, hydrodynamics
and biological processes through air temperature, isolation precipitation,
speed and direction of winds.
Exceptional blooms depend upon complex biological processes, at the
level of the first trophic system in the ecosystem. They include photosynthesis and growth of the plankton, interspecies competition, predatory
behavior of zooplankton, molluscs and crustaceans, algal sedimentation,
and bacterial decomposition. The so-called Lake of Tunis, for example, is
the site of extreme eutrophication during the summer months, where, in
calm weather, the whole water column may become anaerobic. Nitrite
concentrations may reach 50 times those of enclosed bays in Greek