草藻残体分解过程及其对水质的影响

发布时间：2017-12-27 17:28

本文关键词：草藻残体分解过程及其对水质的影响　出处：《南京师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：水生植物主要包括水生高等植物(水草)及藻类等,其残体分解是湖泊生态系统物质循环的重要过程,不仅影响湖泊水环境质量,同时也会影响湖泊生态系统的稳定。因此,研究草藻残体分解过程及其对水质的影响具有重要的理论和实践意义。通过室内模拟实验,研究探讨了芦苇(Phragmites australis)、马来眼子菜(Potamogeton malainus)、荇菜(Limnanthemun nymphoides)残体及太湖水华蓝藻藻浆混合分解过程,分析了分解过程对水质的影响,主要结论如下：(1)荇菜、马来眼子菜及芦苇残体分解速率差异显著(P0.01)。荇菜分解最快,马来眼子菜次之,挺水植物芦苇分解最慢。三种水生高等植物的分解速率与初始磷含量显著正相关,与碳含量、碳/氮、碳/磷显著负相关(P0.05)。(2)水生高等植物的分解可分为快速分解和缓慢分解两个明显阶段。芦苇、马来眼子菜和荇菜快速分解期分解速率分别达到0.051、0.046、0.123 d-1,缓慢分解期平均分解速率仅为0.001、0.009和0.016 d-1。三种植物残体分解过程中C、N、P的累积系数小于100%,元素均发生净释放,其中P的释放速度大于C、N。(3)水生高等植物残体分解对水质的影响表现出明显的阶段性。总氮、总磷在快速分解期迅速上升,芦苇、马来眼子菜和荇菜组的TN较初始值分别提高了216.0%、270.8%和210.3%,TP则达到了0.14、0.31和0.30 mg.L-1。缓慢分解期,营养盐浓度明显下降,实验后期略高于对照组。(4)相同生物量的不同水生高等植物残体分解对水质的影响有差异性。荇菜组的pH、DO低于其他实验组,TN在前8天最低,实验后期最高。马来眼子菜组TN、TP、NH4+-N、NO3--N在前8天高于其他组。芦苇组TP最低,实验末期,4+-N、NO3--N高于其他组。一定的植物残体介入可加强水体的反硝化作用,有助于水体氮素的去除,实验结束时,各处理组4+-N、NO3--N和NO2--N均显著低于对照组。(5)芦苇和蓝藻藻浆混合分解会引起水体黑臭现象,pH, DO迅速降低,分解在厌氧条件下进行,整个过程伴随着刺鼻的恶臭味。芦苇和蓝藻藻浆混合分解分解对水质的影响表现出明显的阶段性。0-8天,蓝藻和芦苇会迅速分解向水体释放C、N、P,第8天水体TDN、TDP、TOC均达到最大值,分别可达41.88、0.63、294.82 mg·L1,8-64天TDN、TDP、TOC整体呈现下降趋势。(6)芦苇和蓝藻藻浆混合分解过程中,水体中的NH4+-N浓度在0-32天保持较高水平,实验组最高浓度可达15.6、36.72、41.30 mg·L-132-64天呈现下降趋势。NH4+-N在无机氮中占有绝对优势,所占比例大于90%。另外,低溶氧加.剧了反硝化作用,整个过程中,NO3--N和NO2--N都保持较低的浓度。
[Abstract]:Aquatic plants mainly consist of aquatic higher plants (aquatic plants) and algae. The decomposition of residues is an important process of material cycling in the lake ecosystem. It not only affects the quality of lakes' water environment, but also affects the stability of the lake ecosystem. Therefore, it is of great theoretical and practical significance to study the decomposition process of the residue of grass algae and its effect on water quality. Through indoor simulation experiment, study the reed (Phragmites australis), p.malaianus (Potamogeton malainus) (Limnanthemun Nymphoides), Nymphoides residues and Taihu lake algae slurry mixed decomposition process, analyzes the influence of the decomposition process of water quality, the main conclusions are as follows: (1) Nymphoides, p.malaianus and reed residue body decomposition rate was significantly different (P0.01). The decomposition of the fastest, p.malaianus of aquatic plant reed is the slowest. The decomposition rate of three kinds of aquatic higher plants was positively correlated with the initial phosphorus content, and was negatively correlated with carbon content, carbon / nitrogen, carbon / phosphorus (P0.05). (2) the decomposition of aquatic higher plants can be divided into two distinct stages: rapid decomposition and slow decomposition. Fast decomposition period of reed, p.malaianus and Nymphoides decomposition rate were respectively 0.051, 0.046 and 0.123 D-1, the average period of slow decomposition the decomposition rate is only 0.001, 0.009 and 0.016 d-1. The cumulative coefficient of C, N and P is less than 100% during the decomposition of the three plant residues, and the elements all have net release, and the release rate of P is greater than that of C and N. (3) the effects of the decomposition of the aquatic higher plants on the water quality showed a distinct stage. Total nitrogen and total phosphorus in the rapid decomposition period rose rapidly, reed, p.malaianus and Nymphoides group TN compared with the initial value were increased by 216%, 270.8% and 210.3%, TP reached 0.14, 0.31 and 0.30 mg.L-1. In the slow decomposition period, the concentration of nutrients decreased significantly, and the late experiment was slightly higher than that of the control group. (4) the effects of the decomposition of different aquatic higher plants on the water quality of the same biomass are different. The group of pH, DO was lower than that of the other experimental group, TN 8 days before the lowest, highest at the end of the experiment. P.malaianus group TN, TP, NH4+-N, NO3--N in the first 8 days was higher than other groups. In the reed group, the TP was the lowest. At the end of the experiment, 4+-N and NO3--N were higher than those in the other groups. A certain plant residue intervention can enhance denitrification of water body and contribute to nitrogen removal. At the end of the experiment, the 4+-N, NO3--N and NO2--N of each treatment group were significantly lower than those of the control group. (5) the decomposition of reed and cyanobacteria algae will cause the black and odour phenomenon of water body. PH and DO will decrease rapidly and decompose under anaerobic conditions. The whole process will be accompanied by pungent odor. The effects of the mixed decomposition and decomposition of reed and cyanobacteria on water quality showed obvious stages. On the 0-8 day, cyanobacteria and reeds quickly decompose to release C, N and P to the water body. On the eighth day, TDN, TDP and TOC reach the maximum value, reaching 41.88, 0.63, 294.82 mg / L1,8-64, respectively. TDN, TDP and TOC all show a decreasing trend. (6) the concentration of NH4+-N in the water body maintained a high level on the 0-32 day after mixing decomposition of reed and cyanobacteria. The highest concentration of the experimental group reached 15.6, 36.72, 41.30 mg / L-132-64. NH4+-N occupies an absolute advantage in inorganic nitrogen, the proportion of which is more than 90%. In addition, low dissolved oxygen added to denitrification. During the whole process, both NO3--N and NO2--N kept a lower concentration.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173;X143

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