Diatoms (Bacillariophyceae) from Orissa State and Neighbouring Regions, India

Abstract

The Bacillariophyceae are unicellular algae characterized by having a cell wall of silica. The wall consists of two valves that have more or less flat surfaces, held together by a band or girdle. They are found in freshwater and marine habitats, and also on moist soil surfaces. There are only few published records on the systematic account of freshwater diatom flora of the Indian sub-continent. Till date a total number of 173 species of diatoms belonging to 24 genera have been reported from various regions of India (Gonzalves and Gandhi 1953; Gandhi 1956, 1959, 1967; Sarode and Kamat 1979, 1983; Barhate and Tarar 1983, 1985; Somashekar 1983, 1984; Bongale 1985; Prasad and Jaitly 1985; Pal and Santra 1990; Sinha 1997; Kant and Gupta 1998), however, all these work have been confined to certain specific localities of Western and Southern India, e.g. Maharastra, Gujrat and Karnataka states. Orissa state located in the east cost of India (Lat. 17° 48’-23° 34’ N and Long. 81° 24’-87° 29’ E) has an area of 1,55,842 km2 and is rich in water bodies due to its several rivers, reservoirs, lakes, ponds and ditches, streams in the hilly terrain and waterlogged rice fields. Hence it was expected that may diatoms might be occurring in this part of India. So far there has been no record of the fresh water diatoms of Orissa state, in the east coast of India. Through our survey for over a period of three years we for the first time reported 78 taxa of diatoms from Orissa state and its neighbouring regions of which 22 are new to India.