Available algal biomass in tropical brackish water artificial habitats

Experiments were conducted in february 1990 at the Layo aquaculture station located in Ebrié Lagoon, Ivory Coast, to find a reliable technique for the estimation of algal biomass and to understand the process that leads to a high tertiary productivity. Periphyton, growing on bamboo, was sampled at different settlement levels in an "acadja-enclos" at 200 m off the lagoon bank. "Acadja-enclos" is an extensive aquaculture system where #Sarotherodon melanotheron$ (#Cichlidae$), a herbivorous fish, occurs mostly. Organic charge and periphytic concentrations (chl a, pheopigment, total pigments) were determined on each sample (from different locations). Specific microalgae composition and light intensity were also estimated. The periphytic community within the "acadja" was mainly composed of filamentous algae with #Rhizoclonium$ (Kutzing) (#Chlorophyceae$) as the major genus. Cyanobacteria and many species of the diatom #Nitzschia$ comprised a high proportion of the epiphytes found. (D'après résumé d'auteur