Biodiversity of cyanobacteria in fresh water ponds of Pudukkottai district, Tamil Nadu, India

Cyanobacteria notably called blue-green algae mostly inhabit moist soils and water. These species constitute a major part of the phytoplanktonic biomass in freshwater ponds. cyanobacteria serve as the significant resource in various applications like medicine, mariculture, feed, fuel, and in combating pollution. Cyanobacterial biodiversity provides various useful insights and is considered an important ecological parameter in freshwater aquaculture. The present research work aims to study the biodiversity of cyanobacteria among 20 different freshwater ponds in Pudukkottai district, Tamil Nadu, India. The samples were collected and pure culture was obtained, followed by maintenance in the BG-11 medium. The species were identified and classified based on the size, shape, and color (morphological features) of the blue-green algae using a trinocular microscope. The physicochemical characteristics such as pH, temperature, biological oxygen demand, chemical oxygen demand, etc., of the freshwater ponds were also studied as they greatly influence the cyanobacterial biodiversity. The abundance of cyanobacteria was seen in a low amount of dissolved oxygen, pH of 8.0 with high oxidizable organic content. About 42 distinct cyanobacterial species were isolated consisting of 25 versatile families of cyanobacteria. Chlorophyceae was found to be predominantly present in the fresh water ecosystem, followed by Cyanophyceae, Bacillariophyceae, Ulvophyceae, and Dinophyceae. The present study revealed the biodiversity of blue-green algae from the fresh water ponds of Pudukkottai District which holds as the baseline data for the more detailed studies in future.