Abstract
Cyanobacteria are widely distributed in natural waters. They constitute the major proportion of total primary production in tropical, sub-tropial and temperate waters. Present research was conducted on biodiversity of epiphytic, epizoic, epilithic, planktonic and edaphic cyanobacteria from a rocky shore (Buleji) and mangrove swamps (Sandspit) backwaters, on the Karachi coast. A total of 191 species of cyanobacteria were recorded in samples collected from rocky shore and mangrove forest. Out of which 92 species were recorded from only one niche (Table 1) while the rest of the species occurred commonly in various habitats. The highest number of cyanobacteria (124 species) were recorded as epiphytic species associated with green, brown and red seaweeds, followed in descending order by edaphic (73 spp), epizoic (65 spp), epilithic (57 spp), rock pool water (44 spp), mangrove swamp (42 spp) and coastal water (29 spp). Phormidium was the most dominant genus recorded from all habitats containing 39 species, the second most abundant genus was the Oscillatoria (33 species). Out of 192 species 93 species have been observed from a single habitat, such as, epiphytic (42 spp), epizoic (13 spp), epilithic (9 spp), edaphic (13 spp), rock pools (2 spp), coastal water (3 spp) and mangrove swamp (11 spp).
