Influence Of Environmental Factors On The Velocity Of The Growth And Calcification Of The Cyanobacteria

The deposition of cyanobacteria plays the significant role in the forming process of the travertine ,which generally exists in the karst areas. Simulating the natural growth conditions, the thesis carries out an experiment on five kinds of cyanobacteria. By contrasting and analyzing the biomass,cell growth rate, culture medium pH value and culture medium Ca2+ concentration, and observating of scanning electron microscope photography, the author screens out two cyanobacterial species (Synechocystis sp. and Scytonema hofmanni Ag.) of quicker velocity of growth and calcification . These two cyanobacterial species are the object of the experiment. The author studies on the influence of environment factors on the velocity of growth and calcification of cyanobacteria.The result of experiment as follows :1.Within the range of testing condition, when hydronamic is range from 0 to 60rpm, the velocity of growth and calcification of Synechocystis sp. and Scytonema hofmanni Ag. is quicker.2. Within experiment condition range, when the culture medium pH value is range from 6.5 to 8.5 , the velocity growth and calcification of Synechocystis sp. and Scytonema hofmanni Ag. is quicker, and when the culture medium pH value is 9.5, the growth and calcification of cyanobacteria is restrainted to a certain extent. 3. Within experiment condition range, when the intensity of illumination is 3000lux , the velocity of growth and calcification of Synechocystis sp. and Scytonema hofmanni Ag. is the quickest.4. Within experiment condition range, when the temperature is 25℃, the velocity of growth and calcification of Synechocystis sp. and Scytonema hofmanni Ag. is the quickest. The velocity of growth and calcification falls when the temperature is low.5. Within experiment condition range, when Ca2+ concentration of the culture medium is low, the growth velocity of Synechocystis sp. and Scytonema hofmanni Ag. is quick; when Ca2+ concentration of the culture medium is high, the calcification velocity of Synechocystis sp. and Scytonema hofmanni Ag. is quick.6)The thesis explores the cause of the formation of the river travertine, putting forward the viewpoint that hydronamic-biology is the genesis of the river travertine.