Abstract:
Blue - green algae (Cyanobacteria) are widespread in nature and they are the primary producers in marine environment. Carbon fixation by cyanobacteria is the most common process in natural waters and also contributing to ammonia assimilation to some extent. To find out the efficiency of cyanobacteria in ammonia assimilation in a marine ornamental fish culture tank was studied, the blue green algae such as Oscillatoria nigra, Lyngbya majuscula, Spirulina plantensis, Chroococcus turgidus, Aphanocapsa delicatissama, Nitzschia palaceae were identified, screened, developed as mass culture and used for the study. Two ornamental fish culture tanks were selected as control and experimental. The Physico-chemical parameters along with ammonia were monitored during the study period. In the control tank, little elevated level of ammonia was recorded (0.44 to 1.72mg/l) and in the experimental tank, the low value of ammonia was recorded (0.44 to 0.09mg/l). The present study revealed the clear uptake of ammonia by cyanobacteria and the growth of cyanobacteria was also monitored by analyzing the chlorophyll content in the water. The initial chlorophyll value in the control and experimental tanks both were recorded as 0.0µg/l. The higher level of chlorophyll (17.87µg/l) was recorded at the end of the study in the experimental tank than the control tank (1.2µg/l). The isolated and identified micro algae (cyanobacteria) were maintain the water quality parameters in fish culture tanks mainly assimilation of ammonia and reduce the toxic level and sustain the growth of fish
