VERTICAL DISTRIBUTION OF PHYTOPLANKTON COMMUNITY RELATED TO WATER QUALITY IN BOUKERDENE RESERVOIR, NORTH OF ALGERIA

Samia HOULI, A. AOUABED, N. BOUAICHA, Fadila AMMOUR

Résumé


Abstract:
Phytoplankton is sensitive aquatic organisms, and their composition and abundance can reflect the
eutrophic situation in a reservoir. Thus, eutrophication is defined as development of phytoplanktonic
blooms caused by the increase in nutrient concentration in aquatic ecosystems, inducing the
degradation of their quality. Indeed, different human activities generate wastes that cause changes in
the natural hydrological conditions of the aquatic system, and induce eutrophication. In this regard, the
objectives of this study were to characterise the phytoplankton composition and vertical distribution of
biomass in relation with abiotic variables regulating its development.
The lake Boukourdane studied, is located in northem Algeria, in a sub-humid area. The analysis of
phytoplankton community composition, showed five groups which were Diatomophyceae,
Dinophyceae, cyanobacteria, chrysophyceae and Chlorophyceae. Diatomophyceae are the
dominant organisms in the phytoplankton community in spring,in summer and in autumn. While, on
surface, Chlorophyceae dorninated in November to February and in December to January at 5 m
and 20 m depth. Likewise, with increasing depth,the phytoplankton community evolving in Lake
Boukerdene have undergone a significant decline, which has reduced the number of species and
their density
Analysis of nutrient indicates that there is a temporal and a vertical variation in the reservoir.
Nevertheless, the hydrological factors and the temperature related to the climate would be two of
the principal causes of the temporal variations of the species.

Mots-clés


phytoplankton; cyanobacteria; waterreservoir; eutrophication; nutrient.

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