AN ECOLOGICAL ASSESSMENT OF ALGAL GROWTH WITH PARTICULAR REFERENCE TO BLUE-GREEN ALGAE FROM UPPER BRAHMAPUTRA VALLEY OF ASSAM

Abstract

The ecological assessment of algal growth of the present study area i.e. Upper Brahmaputra Valley, Assam is very infancy. The present study revealed that the algal growth depends mainly upon the water holding capacity of the soil and abundance of water which is correlated with the initiation of rainfall. It has also revealed that the rainfall and abundance of water is not the only factor for optimum growth of BGA. Temperature may also play a vital role for the luxuriant growth of BGA along with the abundance of water. Besides, we have noticed that BGA diversity is more in virgin low lying area than other areas. It has seen that in most of the rice fields situated nearby tea garden of the study area has significantly less species diversity of BGA. It is perhaps due to indiscriminately used of chemical fertilizers as well as other chemical herbicides and pesticides in the tea gardens. And also notice that there are no any BGA in the crude oil contaminated paddy fields as well as in other low lying areas near by it. In such area the surface of the water bodies and soil surface is covered completely by crude oil, released from oil digs and Gas Gathering Station (GGS). However, abundance of BGA has gradually increased with the increasing of distances from the point of oil digs and GGS.