| Through sampling and analyzing algae species in natural water-body of the Yangtze river and the Jialing river located at Chongqing urban section along the Three-Gorges valley, and combining with monitoring on the influencing parameters to algae growth, such as TN/TP, light intensities and current velocities by experimental simulation, the effect on the algae propagation behavior has been studied systemically. The results show that under static hydrological condition with various TN/TP and light intensities the Chlorophyta and Cyanophyta would grow rapidly while the Bacillariophyta disappear quickly, and other algae species had little change, and the total algal cell density could exceed 107cells/L. However, even if under lower current velocity as about 0.03 m/s, the total algae cell density would increase at most obviously while its density could only reach 106cells/L, and the proportion of Bacillariophyta would increase with the increase of current velocity, the proportion of Chlorophyta and Cyanophyta begin decrease at same time. Apparently, evolution of the dominant algae species would take place according to the change of hydrological condition. The density of total algae is primal regressed to TN/TP and current velocities with coefficients of determination (RR) are all over 0.93 while it has lower regression coefficient with the light intensities. The samples analysis of the above two rivers under natural state also demonstrates that total algae density in the Jialing river is higher than that in the Yangtze river, and the Bacillariophyta has the absolute domination, and then are Cyanophyta and Chlorophyta, which fit in with the experimental results in our laboratory. |
