Studies On The Contributions Of Carbon,Nitrogen And Phosphorus From Typical Anthropogenic And Natural Sources And Travertine Deposition In Jiuzhai And Huanglong Scenic Area

In this paper,by studying the water and travertine present situation in the Jiuzhai and Huanglong Scenic Area,the plank dust was selected as the typical anthropogenic source of carbon,nitrogen and phosphorus in the Jiuzhai and Huanglong Scenic Area,and the plant litter leaves as the natural source of carbon,nitrogen and phosphorus in the Jiuzhai and Huanglong Scenic Area.Then,a simulation experiment was conducted to estimate the carbon nitrogen and phosphorus contribution and contribution ratio of the plank dust and plant litter leaves,and the effects of plant litter leaves and their carbon,nitrogen,and phosphorus leaching substances on the deposition process of calcium carbonate and sediment products.Further enriching the theory of biological participation in natural travertine deposition is of great significance for maintaining the sustainable and healthy development of the Jiuzhai and Huanglong Scenic area ecosystem.The results show that the TOC concentration in the water of the Jiuzhai and Huanglong Scenic Area is high,and the TN and TP are in excess of the standard.The traces of apparent biological participation of travertine in the Jiuzhai and Huanglong Scenic Area are strongly correlated with the total carbon,nitrogen and phosphorus content of travertine and calcium carbonate.The heavier the traces of travertine apparent biological participation,the higher the travertine nitrogen and phosphorus content,and the lower the calcium carbonate content in travertine.The 48-hour carbon,nitrogen,and phosphorus leaching laws of the plank dust and plant litter leaves are similar.The TOC,TN,and TP dissolution amounts show a rapid initial dissolution and then slowly increase.Their carbon,nitrogen,and phosphorus dissolution ratios are all TP>TOC>TN.At the same time,the particle size is the main factor affecting the dissolution of TOC and TN in the dust along the path.The total nitrogen and total phosphorus of the leaves are the main factors affecting the dissolution of TN and TP in the plant litter leaves.By further estimating the potential contribution of typical anthropogenic and natural sources of carbon,nitrogen,and phosphorus in the Jiu-Huang Scenic Area,the results show that the total potential contributions of carbon,nitrogen,and phosphorus in plank dust and plant litter leaves are 22953.18t,2374.10t,1602.46t.The contribution of plant litter leaves to carbon,nitrogen and phosphorus accounts for more than 99.9%,which plays an absolutely dominant role in the regional carbon,nitrogen and phosphorus contribution.And correspondingly put forward prevention and control suggestions.The saturated calcium bicarbonate solution prepared in the laboratory is divided into three consecutive stages according to time during the deposition of calcium carbonate,a wave stabilization stage,an accelerated deposition stage,and a deposition stable stage.In the travertine deposition simulation system of plant litter leaf action,the TP substance in the solution of the experimental group will be co-deposited with calcium carbonate,and the morphology of the product after 48 hours of deposition in different experimental groups is very different.The deposition process has two effects at the same time.One is that the phosphate substances leached from the plant leaves chelate Ca²⁺,thereby blocking the deposition of calcium carbonate,and the other is the promoting effect of the plant leaf template to accelerate crystal nucleation.Microcalorimetric analysis further confirmed that plant leaching substances can block calcium carbonate deposition,while plant leaves can promote calcium carbonate deposition.In the high supersaturated calcium bicarbonate solution deposition system,green algae has no significant effect on the rate of calcium carbonate deposition,but has a significant effect on the morphology of the deposited product.The polysaccharides secreted by green algae will slow down the deposition of calcium carbonate in the short term,but the larger the biomass of green algae,the more it can promote the deposition of calcium carbonate.The deposition process can not only induce calcium carbonate to form aragonite,but also cause dissolution of calcium carbonate crystals.