Effects Of Different P Concentration,Nitrogen Sources And Aeration Parttens On Growth Of Algae In Freshwaters

The effects of phosphorus concentration,nitrogen sources and aeration patterns on growth of algae in freshwaters were studied in laboratory experiments. The level of phosphorus concentration was set at low phosphorus(LP,0.02mg/L),moderate phosphorus(MP,0.10mg/L)and high phosphorus(HP,1.65mg/L), the nitrogen sources included ammonia nitrogen(A series) and nitrate nitrogen(N series),respectively. For each phosphorus level and nitrogen sources,three modes of aeration were selected,including control,aeration during the day,and aeration at night.â‘ The results showed the cell multiplication of algae was accelerated by increasing of P concentration in the medium. Moreover, when TP=1.65mg/L, the growth of algae was restrained by content of P in the water system.â‘¡On the earlier phase of the experiment , algae in the ammonia nitrogen treatments grow well . Several days later , algae in the nitrate nitrogen treatments grow better .In ammonia nitrogen treatments, cyanophyta becomes dominant species easily. In contrast, chlorophyta dominant in nitrate nitrogen treatments.â‘¢The different aeration treatments shows different effects on algal growing: Day-only aeration can expedite the algal growth cycle, in contrast , night-only aeration inhibits algal growth obviously. In nitrate nitrogen treatments, day-only aeration can accelerate the P-in-cell of algal. In contrast, day-only aeration affects the P-in-cell of algal litter in ammonia nitrogen treatments.â‘£The correlation of chlorophyll a and phosphorus concentration was depended on the growing status of algae, the better growing of algae and the higher mean value of chlorophyll a ,the more obvious of the correlation of chlorophyll a and phosphorus concentration.