Abstract
The knowledge of the variation of the components of the watery ecosystems is
necessary to understand the mechanisms of operation of these ecosystems in order to
justify certain interventions for example : installation of an aquacultural site.
Within the framework of a prospection of the aquacultural potential of the
Boukourdane dam (wilaya of Tipaza), this study describes the ecological evolution of
this water level through a monthly sampling during an annual cycle (from January
2005 to December 2005) of the physicochemical parameters (temperature, pH and
dissolved oxygen), chemical parameters (ammonia, nitrites, nitrates, orthophosphates
and silicates) and trophic parameters (suspended matter, chlorophyll a and
zooplanctonic biomass).
The examination of the monthly averages of the water level of the dam during the ten
last years (1996-2005) revealed a weak monthly change of the water level with a
volume always higher than 32 million m
3 .
The results obtained show that the Boukourdane dam presents high oxygenate water
which is slightly alkaline.
The contents nutritive salts observed in the dam Boukourdane are very weak in
comparison with the strong concentrations raised in other Algerian dams. This is can
be the result of the importance of the photosynthetic activity during the year 2005 in
the Boukourdane dam which vary between 0,68 mg/m
3 and 5,04 mg/m
3 of chlorophyll
a.
Principal components analysis revealed a negative correlation beteween the silicates
and the temperature of water of the Boukourdane dam and it reveals a regrouping
between chlorophyll a, dissolved oxygen, the zooplanctonic biomass and the
suspended matter opposed to nitrates and orthophosphates.