Purification Efficiency Of Submerged Macrophytes For The Wetland Environment In Baiyangdian Lake

Control the eutrophication of Baiyangdian Lake has becamed a problem to solve, should take some measures to improve the environment of the wetland of Baiyangdian Lake. Submerged macrophytes are the key to repair the environment of water. This research investigated the submerged macrophytes of Baiyangdian Lake, and made sure Potamogeton crispus is the preponderant species of Baiyangdian Lake, combine other submerged macrophytes to conside the purification efficiency of submerged macrophytes for the wetland environment in Baiyangdian Lake. Provide theoretical basis to prodect the ecosystem of Baiyangdian Lake.This research mainly on the following job:(1) Made different nutrition liquids of nitrogen and phosphorus, in the condition of low nutrition,middle nutrition,high nutrition,rich nutrition and exceed rich nutrition to compare the improve efficiency to water.(2) Different simulated static systems were built to study the growth of Potamogeton crispus and its effect on removal the nitrogen and phosphorus from eutrophic water and sediment.(3) Taking the Potamogeton crispus collected from Baiyangdian Lake, in different growth periods analyse the wate,nutritive value changes and made sure the best harvest time of Potamogeton crispus.(4) Static simulation tests were carried out in lab to study the effectivenes on the improve water of Baiyangdian Lake.Through the above researches, conclusiones are as follows:(1) Potamogeton crispus in the condition of middle nutrition,high nutrition,rich nutrition and exceed rich nutrition growth well, the lowest removal efficiency of NH4+-N,TN and TP were 88.18%,18.53% and 53.15%. The absorb manner of Potamogeton crispus to TN is exceed, and to TP is sedimentation. Sediment is playing an important role in nutrients removal.(2) Different growth systems of Potamogeton crispus have different Purification efficiency to water. The fitted equations indicated that NH4+-N,TN,TP and CODcr were negatively exponentially decreased with time. The best removal efficiency of NH4+-N,TN,TP and CODcr were 90.97%,73.3%,87.9% and 58.25%.(3) The results showed that Potamogeton crispus biomass increased at the exponential growing stage, the concentrations of dissolved oxygen risd, chemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus and orthophosphate levels declined in Baiyangdian Lake.The content in the area with Potamogeton crispus was significantly better than the area without Potamogeton crispus. Potamogeton crispus growth absorbed the nitrogen,phosphorus and organic matter from the sediments, and inhibit the pollutants release from the sediment.(4) In exponential growth phase of Potamogeton crispus biomass increase, the content of crude protein,crude fat,Total P andβ-carotene reached the largest, in the monitoring of month 3-6, the content of Crude fiber, crude ash, calcium and Vc showed a gradually rising trend. The content of crude protein more than 100 g·kg^-1, the content of Crude fiber below 155 g·kg^-1, the content of crude fat more than 12 g·kg^-1 the content of crude ash more than 140 g·kg^-1, the content of Ca and total P more than 3 g·kg^-1, the content of Vc more than 140 mg·kg^-1, the content ofβ-carotene more than 310 mg·kg^-1, in the whole growth periods of Potamogeton crispus, every sampling site. The nutritive value of Potamogeton crispus more than other hydrophytic feeds, Potamogeton crispus was the most perfect feed to fish and domestic animal.(5) According to the water and nutritive value change, the best season of Potamogeton crispus harvestry is the beginning of May.(6) The order of TN removal ability was: Ceratophyllum demersum,Hydrilla verticillata,Potamogeton malainus,Potamogeton pectinatus, and the removal efficiency more than 79.4%; The order of TP removal ability was: Hydrilla verticillata,Ceratophyllum demersum,Potamogeton malainus,Potamogeton pectinatus, and the removal efficiency more than 83.59%.