The water available to humans, and also to the rest of the ecosystem, represents less than the total volume of fresh water on earth. The quality of the part available and potentially usable by man has continued to deteriorate and sometimes in an irreversible manner. The generating capacity is exceeded because of our increasingly significant liquid, solid or gaseous toxic discharges. In order to contribute to the knowledge of the biological and physicochemical quality of aquatic ecosystems, the study of Lake Kivu in South Kivu in the coastal zone of the Mulambula district, in the commune of Bagira, City of Bukavu is essential. This work aims to characterize the mechanism of the ecosystem by monitoring the interaction between the two elements biotic (biodiversity) and abiotic (environmental factors) likely to cause their modification or development and to control them.