A study of bluegreen algae in the paddy fields of golaghat subdivision of district Jorhat state Assam

Abstract

A research on the blue - green algae available in the paddy fields of Golaghat sub - division of the State of Assam was carried out. This investigation dealt with the occurence and distribution of blue - green algae in various habitats in general and in the paddy fields in particular. the study was carried out during 1983 - 1986 basing on live specimens collected from different localities of Golaghat sub - division at different periods of the year. Of all the reported genera of blue - green algae reported from the area, Oscillatoria Emerges to be the most dominant over other genera and is found to occur throughout the year. When all the available blue - green algae are taken into consideration, in relation in their growth and population, it is seen that all of them show a similar pattern of growth. However, when growth periodicity of the individual genus is concerned it is seen that depending upon environmental factors slight variation is seen in their first appearence and subsequent growth. The appearence and growth of blue - green algae seem to have a direct relation with the onset of monsoon or of the summer months or both together. If monsoon or the rainy season starts early causing abundance of rain water in the paddy fields then blue - green algae make their appearence early and show vigorous growth. If, however, rains start late during the season then algae belonging to other groups viz. green algae and diatoms dominante over blue-green algae. Temperature play a key role on the growth of blue - green algae along with abundance of water. This is very much clear when the case of blue - green algae available in hot water springs are compared to those growing in cold water bodies lying very near to hot - springs. Day length seems to play a minor role on the growth of blue - green algae. The extracellular products of blue - green algae may either accelerate or inhibit the growth of other algae or plants growing in the same area. Paddy fields lying near the tea - estates show only presence of Oscillatoria which...