Effect of different concentrations of mercuric iodide on the growth of Microcystis spp.

Abstract

Cyanobacteria are commonly called as blue green algae which are abundantly distributed in both aquatic and terrestrial ecosystem. They are procaryotic autotrophic organisms and have thallus structure. Such organisms are actively involved in the biological nitrogen fixation which can fix the atmospheric nitrogen and converts into ammonia compounds. Plants can utilize such converted components for their growth and metabolic activities. Since they are diazotrophs which is the suitable supplement to soil as a nitrogenous fertilizer. The present study analyzed the impact of mercuric iodide concentrations on the selective cyanobacteria: Microcystis spp. Initially the Microcystis spp. were isolated from the paddy field soil of Selugai, Sivagangai district, Tamil Nadu. The isolated organisms were mass cultured and treated with various concentrations of mercuric iodide (0.1 ppm to 1 ppm) under laboratory condition. The present study reported that the various concentrations of such heavy metal enhanced the Microcystis populations. It concluded that Microcystis sp . well grown at the low concentrations of heavy metals and the higher concentration minimized the Microcystis growth when compared to control. This work confirmed that the accumulation of cyanobacterial species in the paddy field pretentiously fixed atmospheric nitrogen and showed the tolerance effect against the various applications of agrochemicals with heavy metals generally applied in crop field.