S. Gupta and K. Buragohain
Abstract
Red tides caused by Euglenoid protozoans are common in the floodplain wetlands of Barak Valley, Assam, North-East India. Though the presence of Euglena renders water unfit for drinking, its role as food for surface feeding fishes makes it important to fish farmers who artificially induce euglenoid bloom for augmenting fish production. A study on the fluctuations of the chemical parameters, major phytoplankton taxa and chlorophyll concentration of phytoplankton from morning to afternoon in five ponds revealed that no specific pattern could be discerned in the concentration of chemical parameters except Mg, Chlorophyll a and free CO2. Concentration of Mg and free CO2 were lowest in the afternoon in all the five ponds and chlorophyll a was found to be highest in the morning in all the ponds except pond 1. DO showed significant positive correlation with chlorophyll b, NO3 and TA. Mg was found to be significantly positively correlated with TA, conductivity, TDS, Zn, chlorophyll a and free CO2. No significant relationship of phytoplankton taxa with chemical parameters was recorded. Euglenophyceae showed significant positive relationship with Chlorophyceae and significant negative relationship with Bacillariophyceae.