Research On The Relationship Between Plant Community And Reduction Of Phosphorus And Nitrogen In Ecological Pond For Reusing Water

This research was conducted in the ecological pond for reusing water at Quanshang mine in Tengzhou of Shandong province from November2010to November2011. The aquatic plants and water were concentratedly and regular sampled to systematically analyze the relationship between water quality parameters (WQP) throughout the year and the distribution of the community and the relationship between WQP and the nitrogen and phosphorus contents in plant within the communities. The ecological health of the pond was assessed as well based on the investigation.The results were shown as follows:(1) Comparing the effect of the four plant communities on the reduction of nitrogen and phosphorus in the water, the reed and typha communities played the main role, followed with the lotus communities> the submerged plant communities.(2) The water in the ecological pond was of alkalescence with a high level of dissolved oxygen, and the conductivity gradually decreased from the inlet to the outlet.(3) The nitrogen and phosphorus contents in the water in aquatic plant communities was obviously decreased along with the water flow direction.(4) The pollution load of nitrogen and phosphorus were heavily decreased although the water quality of the inlet was greatly fluctuated. And the total phosphorus and PO43--P contents in the outlet were stable during the entire year.(5) The ecological health of the pond changed gradually from severe eutrophication (>70) to mild eutrophication (50to60) along with the water flow direction. The health of the water in the pond was better than average in whole and no algal bloom outbreaked.(6) The reduction of nitrogen and phosphorus in the water by aquatic plant communities was marked. However, the accumulation of nitrogen and phosphorus in aquatic plants was limited. Therefore, the mechanism of nitrogen and phosphorus reduction in the water of the ecological pond should be further studied.The relationship between the plant communities and nitrogen and phosphorus reduction in ecological pond for reusing water is an important scientific question in both environmental and ecological engineering fields. This study revealed the relationship of the aquatic plant communities in the ecological pond and the reduction of nitrogen and phosphorus pollution load in the water in individual, community and ecosystem scales, and evaluated the ecological health of the ecological pond. It is instructive for eco-construction and the project practice of water quality improvement in the ecological pond for reusing water.