To investigate the input of combined nitrogen by cyanobacteria in mangrove ecosystems and the seasonal fluctuation of this biological process, in situ nitrogen fixation activity was measured in day and night experiments carried out at Maruhubi mangrove ecosystem adjacent to Zanzibar town. Sampling was done for 12 months at two stations: Station I covering sandy sediments and Station II muddy sediments. Associated cyanobacteria genera were identified and environmental variables were measured throughout the study period. A total of 10 genera of cyanobacteria were encountered, two of which were the heterocystous cyanobacteria genera Anabaena and Rivularia and eight the non-heterocystous genera Aphanocapsa, Merismopedia, Lyngbya, Microcoleus, Oscillatoria,... |