The Study On Growth And Competition Characteristic Of Microcystis Aeruginosa And Scennedesmus Quadricanda

The paper based on the subject "lake nutrient criteria and eutrophication control standard reasearch" and choosen Microcystis aeruginosa and Scennedesmus quadricanda as the experiments algae in order to observe their characteristics of phosphate adsorption and population growth by indoor simulation experiments.First of all,to observe different algae's characteristics of phosphate absorption and population growth under different cultures(batch culture,chemostat culture).Second to observe the characteristics of rapid phosphate absorption by the algal cells which were in differdnt starvation growth cultures(0hours,30hours and 60hours).Finally to compare their growth results in the accrete experiment.Combining with algae's characteristics of phosphate absorption and population growth to explain which one will has the competitive advantages in the accrete experiment.The study showed that under batch culture,both of algae had higher half-saturation, max specific growth rate and max biomass than chemostat culture.Microcystis aeruginosa's half-saturation was higher than Scenedesmus quadricauda while max specific growth rate and max biomass was lower than the latter.Both of Microcystis aeruginosa and Scenedesmus quadricauda could absord phosphate on cells and achieved the max absorption value before biological absorption process.As the starvation growth culture was longer,the phosphate disappearing rate was higher.For Microcystis aeruginosa,as the starvation growth culture was longer,the max absoption value was higher and the time which begin to biological absorption was shorter.While Scenedesmus quadricauda had opposite phenomena.Microcystis aeruginosa and Scenedesmus quadricauda would inhibit each other growth when initialize desity keeped 1:1,finally Scenedesmus quadricauda dominated in the competition.By Lotka-Volterm model we could get Scenedesmus quadricauda's competition coeffient was about 3 times than Microcystis aeruginosa's.Under the setting experinmental condition,Scenedesmus quadricauda had higher affinity to phosphate,specific growth rate,absorption rate and needed shorter time to begin absorb phosphate than Microcystis aeruginosa,so Scenedesmus quadricauda showed it's advantage in competition.