Dynamique des communautés phytoplanctoniques du lac Nokoué

Abstract

Phytoplankton is an important element in aquatic ecosystems. It plays a major role in the biogeochemical cycles of the earth planet. The aim of this study is to contribute to the study of phytoplankton dynamics in Nokoué lake and to propose a strategy for the implementation of a coupled modeling allowing the study of the growth of phytoplankton communities found in the waters of Nokoué Lake. Phytoplankton and physicochemical data were collected by potentiometric and spectrophotometric methods during the month of April 2018 at (10) ten points on the lake. As for the data on phytoplankton communities, they were collected using plankton net. The different observations of phytoplankton communities were made under light microscopy. A total of six classes of phytoplankton communities have been identified. The statistical analysis of the data was performed using the RStudio software. The results show a seasonal cycle of phytoplankton communities with both spatial and temporal dynamics. Principal component and redundancy analysis revealed that the dynamics of phytoplankton communities are mainly influenced by temperature, hydrogen potential, nitrates and ortho phosphates. Coupled modeling could promote a long-term study of the evolution of the phytoplankton communities of Nokoué lake and constitute a valuable tool for the management of this environmental heritage of Benin to ensure the sustainability of ecosystem services for local populations.