The influence of filamentous green algae on chlorococcal algae (Desmodesmus spp.)

The allelopathic influence of macroalgae has already been analysed both in marine and freshwater ecosystems. These organisms release allelopathically active compounds to prevent shading by epiphytic and planktonic primary producers. The aim of this study was to determine whether filamentous green algae represented by Cladophora sp. can exert an inhibiting effect on the growth of chlorococcal algae. Two coexisting culture systems differed in the species of Desmodesmus used, medium composition, light source and experiment duration. In both coexistence assays the abundance of microplankton in the controls was greater than in flasks with FGA, which seems to confirm an inhibiting effect by macroalgae on chlorococcal algae.