Growth and periodicity of cyanobacterial bloom in a polluted pond of Agra city.

Periodical changes in physico-chemical properties and cyanophycean bloom in a pond ofAgra city during the year 2005 and 2006 were studied. It was recorded that the pond water was polluted throughout the study period and this was closely associated with Cyanobacterial bloom. During summer (March to June), the pond water was highly polluted, as it was rich in various nutrients and phosphates in particular. The pH of pond water was high with low DO and this was associated with the highest peak of water bloom. On the other hand, during winter (November to January), the bloom was at its lowest. The quantity of various nutrients in the pond water was low and the pH was also low but DO was high. Bloom consisted of eighteen members of Cyanophyceae of which Oscillatoria limosa, O. formosa, O. splendida, Anabeana iyengarii, Microcystis arruginosa and Nostoc muscorum were observed throughout the year. On the other hand, Oscillatoria agardhi, and O. tenuis were found only in winters, while O. annae in rainy season only. Similarly, Oscillatoria brevis, Anabaena flosaquae, Aphanizomenon sp. and Lyngybea birgei were found in abundance in summer.