BIO-ECOLOGIE DES DIATOMEES EPILITHIQUES DE LA RIVIERE MFOUNDI (YAOUNDE, CAMEROUN) : DIVERSITE, DISTRIBUTION SPATIALE ET INFLUENCE DES POLLUTIONS ORGANIQUES/Bio-ecology of epilithic diatoms in the Mfoundi River (Yaounde, Cameroon): diversity, spatial distribution and influence of organic pollution

The aim of this study was to assess the structure of diatom communities in the Mfoundi River in relation to some physico-chemical variables, i.e., analyzing the changes in species composition and the dominance profile of the main species along a pollution gradient. The diversity metrics (species richness, Shannon's diversity index, evenness) and the percent pollution tolerant valves (%PTV) were also tested to characterize the water quality and the response of diatoms to environmental enrichment in organic matter. The physico-chemical analyses of the waters revealed a gradient of increasing pollution from upstream to downstream of the river. The distribution of Nitzschia palea (Kutzing) W. Smith, Navicula geoppertiana (Bleisch) Grunow, Navicula mutica Kutzing, and Pinnularia subcapitata Gregory in the middle and lower reaches was closely related to the organic load and high degree of mineralisation of the waters. N. palea was the most abundant species at the stations Mf5 (66%) and Mf6 (53%).