Lac sud de Tunis : Vulnérabilité hydrobiologique et sédimentologie

Abstract

he aim of this work is to study the evolution of the hydrobiological parametres of the south lake of Tunis during the critical period (july 1994, august-september 1994 and june 1996) and the sedimentological characteristics of this ecosystem. The obtained results show us the high sensibility of the hydrobiological parameters of the lagoon. Their great variations translate a rarefaction of the dissolved oxygen; an excessive turbidity, a high level of organical pollution and a very pronounced eutrofication. As a consequence, specially in the hot months of summer dystrophical crisis are coupled with algae blooms and anaerobical conditions development. The grains size analysis shows that the sedimentary particles are thiner in the lagoon center and coarser towards its borders. Further, the whole lagoon is subject to a silting problem, particulary in its western part and the upper waters of the Rades channel, reducing more the exchanges of waters between the lagoon and the sea.