Effect of nitrate and phosphate concentration on growth of Microcystis wesenbergii and Scenedesmus obliquus

Taking Microcystis aeruginosa and Scenedesmus obliquus as samples, we investigated the effect of concentration of nitrate and phosphate on algal growth. The results show that the maximum inhibitory rates of nitrate limitation on algal growth rate, biomass and chlorophyll content of M.wesenbergii were 2.25%, 2.75% and 40.01%, respectively, while those of S.obliquus were 38.56%, 58.64% and 72.51%, respectively. The maximum inhibitory rates of phosphate limitation on algal growth rate, biomass and chlorophyll content of M.wesenbergii were 11.79%, 10.94% and 51.94%, respectively, while those of S.obliquus were 22.69%, 49.62% and 26.87%, respectively. The positive correlation was observed among nitrate, phosphorus concentrations and algal growth rate, biomass both in linear or exponential types. Growth of S.obliquus was inhibited seriously compared with that of M.wesenbergii at nitrate or phosphate limitation. Lower sensitivity to nitrate or phosphate limitation of M.wesenbergii might support the priority of algal growth and competition.