Study On The Effects And Environmental Factors Of Eco-restoration For Eutrophicated Waterbody With Hydrophytes

Eutropication, which is caused by water body pollution, has become a globalproblem of aquatic environment. With prosperous economy and high density ofpopulation, in the water body of the tai lake, eutrophication is becoming a more andmore serious and important problem which affects sustainable development of societyand economy in the area. So it is of great theory and practical significance to find outthe mechanism and the control technique of the degradation of aquatic ecologicalsystem of water body in the area.Hydrodictyon reticulatum L. and Ceratophyllum demersum L was chosen asorganisms to recover the water body. In this work, their relationship with theconcentration of nitrogen, phosphor, suspended particulate and the autochthons werealso studied. Our results showed that the ecological amplitude of microalgae is thewidest, H. reticulatum comes next and C. demersum the third which indicates that theformer ones would become predominance species in water body with eutrophicationand H. reticulatum is fitter to be used as pioneer specie to recover water body fromeutrophication. The suspended particulate is a double edge sword to recovery plants, inlow concentration it facilitates their growth while in high concentration, due to stress, itinhibits their growth. Under normal conditions the activity of SOD and POD of C.demersum maintains 256-280U/g (green weight) and 80-90 U/g (green weight), thus theactivity of MDA, which is the cellular membrane lipid oxydic marker was under65μmol/g (green weight). When C. demersum was under the high stress of particulatematter more then 300mg/L or when the concentration of microalgae reach 3.02×10~6/m L,the activity of both antioxidase decline rather than maintains high level to cause theaverage level of MDA reaches higher than 79μmol/g (green weight), which oxidativedamage the cell membrane and causes a injure rate of more than 33%.The recovery plants H. reticulatum, C. demersum and native microalgae postinfluence on each other though the competition of nutrients and aiielopathic effect. Theresults suggests that the vacuum filter liquor of the cultivated water of both H. reticulatum and C. demersum can effectively inhibit the growth of microalgae, whichcould effects their normal growth or even causes death of the algae. The inhibit effectsof H. reticulatum and C. demersum is closely related to the concentration of the substancesecrete by the algae which inhibits the growth of other algae: high concentration of thesubstance brings about a striking effect of inhibition which downgrades with the declineof the concentration.In the present work, the recovery effects of the reparation techniques are discussedusing different combinations of the recovery plants. The effects of removing and controleffects of N, P, suspended particulate and microalgae of both the recovery plants aregreat, but with the appropriate combination of them not only the repairing result isbetter but the adaptability of the recovery colony is also greatly enhanced.