Phycological Investigation on Algal Diversity and Nitrogen-Fixing Forms in Paddy Fields

Abstract

The present research investigates the diversity, distribution, and ecological significance of algae in paddy field ecosystems, with special reference to heterocystous and non- heterocystous forms. Paddy fields are semi-aquatic habitats where algal communities play a crucial role in soil fertility, nutrient cycling, and biological nitrogen fixation. Water and soil samples were analyzed microscopically to determine algal composition. The results revealed a dominance of Cyanophyceae (blue-green algae). Among these, heterocystous forms such as Anabaena, Nostoc, Pseudoanabaena constircta, Pseudoanabaena catenata and Cylindrospermum were identified as major nitrogen fixers, while non-heterocystous forms such as Oscillatoria and lyngbya contributed to organic matter production. The findings highlight the significant ecological role of both groups in maintaining soil fertility and enhancing rice productivity. Total 15 Heterocystous and 12 Non-heterocystous Blue-green algae was recorded. Total 27 Cyanobacterial algae were studied.