Study On The Environmental Effect Of Submerged Macrophytes On Eutrophic Water

Water environmental quality improvement and eco-system restoration have received more and more attention both home and abroad. Aquatic vascular plants were the primary producer in the water body, and the environmental effects produced by them were the foundation of water environmental quality improvement. The environmental effects of Elodea nuttallii and Potamogetor crispus on N and P in the water were studied, and it involved following aspects:(1) The effect of submerged macrophyte on the polluted water was studied, and it showed that the effects were acted as reducing turbidity (the highest pure reduction rate was 87.9%), enriching oxygen (the highest pure increasing quantity was 3.3mg/L) , and reducing nutrients(the highest pure reduction rate of TN was 43.0%) .(2) The effect of submerged macrophytes on the N and P in the different conditions of water quality was studied, and it showed that the N concentration in water column was the first influence factor to nitrogen content containing in Elodea nuttallii, and the N form was the first influence factor to nitrogen content containing in Potamogetor crispus, the N/P was was the first influence factor to phosphorus content containing in Elodea nuttallii and Potamogetor crispus, and the absorption rate of nutrients of Elodea nuttallii was quicker than that of Elodea nuttallii.(3) The effect of different water quality on the decomposition of submerged macrophytes was studied, and it showed that Elodea nuttallii and Potamogetor crispus could be best rottenned and decoposited in the water riched of N and P, and the decomposition rate as well as the the release of phosphorus of Potamogetor crispus was quicker than that of Elodea nuttallii.(4) The effect of submerged macrophytes on the water of high ammonia nitrogen was studied, and it showed that the reduction rate of NO3-N and NH3-N in the tank which let pH go was quicker than that in the tank which adjusted the pH to 7.5 constantly.(5) The effect of the mass balance of N and P was studied, and it showed that the vast nitrogen could be removed by the effect of microorganism and sedimentation, while the suspended phosphorus could be fastly removed from the water column by sedimentation, and the dissolved phosphorus could be mainly removed by plants' absorption.