The Studies On The Effects Of Suspended Sand On The Algal Growth In The Eutrophic Water Of The Three Gorges Reservoir

Eutrophication was named "ecological cancer" usually in waterbody, from which we could see the dead harm of eutrophication. Because of the negligence of management, in addition, the ecological environment was destroyed gradually. A large number of lakes and rivers all over the world came into eutrophication. It intimidated natural harmony and human's health. When a waterbody got into the state of eutrophica, the nutritional elements were absorbed by hydrophytic biology. The aerobic algae increased rapidly, and created dominant species in waterbody. This is so called "water bloom" or "algal bloom".The Three Gorges Reservoir (TGR) was season-adjusted and belongs to the mode of riverway, which has the characters of river and reservoir. The waterbody had changed markedly when water storage, so it brought the hidden trouble of "water bloom" in the TGR. The algae were affected by the corelations of several factors, such as hydraulics, weather. So the algal growth was complex. At present, people paid more attentions on these aspects gradually, the methods on researches and analyses were manifold.There are few researches on the influences of the suspended matters on the algal growth, however, their effects were important and unneglected. We could conclude from three aspects as followed: (1) The obstruction for light entered into water; (2) release or adsorption of nutritional matter in waterbody; (3) provide better environment for algal growth as carrier. We chose the sand as the suspended matter to study the effects of them on the algal growth. In order to understand the mechanism of algal growth from new points, then provide new methods restricting the algal growth and basic informations controlling the "water bloom", a series of experiment were started in the lab.After the indoor experiments, we obversed the changes of pH and DO value in the growth of algae in the Three Gorges Reservoir. We also summarized the effect of light on the algae, studied these effects from particle sizes and concentrations of sand, and assembled a function from three aspects. We brought F to denote the restriction, put forward a half-ration A to be the threshold of the algal growth. And the parameters could be called the critical parameters when F=â–³. The critical particles sizes and concentrations were 360mg/L and 0.19mm respectively in our experiment. A new format was got when the function of suspended matters added in the former model of algal growth. In the new format, a series of parameters was undecided.