【作者】 周莹；

【导师】 李玥莹； 台培东；

【作者基本信息】 沈阳师范大学 ， 分子生态学， 2016， 硕士

【摘要】 随着工农业技术的进步和人口城市化的飞速发展,越来越多的生活、农业及工业污水流入水环境,导致我国水环境逐年恶化,水污染问题尤为严重。水作为人类生存的第一要素,水质的恶化直接威胁到人类的健康。通过检测水体中各类污染物及其浓度变化趋势评价水质状况,为防治污染提供技术支持。溶解氧(Dissolved Oxygen,DO)是各种好氧水生生物正常代谢的基本保障,也是水体自净能力一项重要指标,被各级监测点日常监测与应急监测列为首选项目。本文采用室内模拟试验,通过膜电极法(溶解氧测定仪,JPSJ-605),分别控制藻类密度、温度、底质和生物量四个因素,研究在不同因素下水体DO日变化规律。并通过线性回归分析,以期找出各因素与溶解氧之间的相关性,在一定范围内计算出各因素与溶解氧的定量关系式,进而探究各因素对水体溶解氧变化的影响。藻类作为水体的重要初级生产者,其生长代谢对水体溶解氧变化的影响及响应非常敏感。白天水体藻类进行光合作用释放氧气,DO增加,夜间藻类呼吸消耗氧气,DO降低,造成水体DO较大的昼夜差值。水体中溶解氧随着光照强度变化呈规律性变化,即随着光照强度增加,藻类光合作用增强产氧多,在下午某一时间点光强达到最大值,水体DO值亦达到最大值;随着光照强度减弱,藻类光合作用降低产氧少甚至不产氧(无光照条件下),DO值降低。水体中藻类密度处于某一节点时,光合作用产氧和呼吸作用耗氧能够达到动态平衡,水体DO昼夜差变化也不显著,基本维持在稳定水平。水生动物一系列新陈代谢(呼吸、运动、维持体温)需要消耗水中的氧。研究发现,生物量与溶解氧呈显著负相关,DO随着生物量增加而降低,且生物量过多时会出现死亡现象。经分析可得,生物量与溶解氧之间的Spearman相关系数r=-0.820,其显著性水平P=0.001?0.01,二者的线性相关方程为Y(DO)=6.310-0.194X(Biomass)(R2=0.793)。水温对水体DO的影响主要是影响氧气在水中溶解度。研究发现,水温与溶解氧呈显著负相关,DO值随水温的降低而升高,并且具有显著线性关系。经分析可得,温度与溶解氧之间的Spearman相关系数r=-0.690,其显著性水平P=0.013?0.05,二者的线性相关方程为Y(DO)=10.745-0.204X(Temp)(R2=0.648)。底质中存在的微生物及耗氧有机质等是消耗水中氧气的主要因素。理论上随着底质量的增加,其对水体中溶解的氧消耗越多,但在实验中发现,DO值并非随着底质量的增加而降低。加入底质的三个实验组,水体DO值均有所降低,加入底质量少的实验组反而比底质量多的实验组耗氧多,底质量增加,处于厌氧环境,降低耗氧率。更多还原

【Abstract】 With the progress of industrial and agricultural technology and the rapid development of urbanization, more and more domestic sewage, industrial and agricultural wastewater were discharged into the environment, leading to water quality deterioration yearly, and water pollution becomes a particularly serious problem. Water is the first factor of the survival of mankind, so water quality deterioration directly harms to people’s health. Water quality is evaluated by detecting all kinds of pollutant and its change of concentration in water, which can provide a technical support for pollution control. Dissolved oxygen(DO) is the basic guarantee of normal metabolism of various aerobic aquatic organisms, and is also an important indicator of water body self-purification, at the same time, it is served as top priority of daily and emergency monitoring.Based on simulated experiment, through membrane electrode method, this paper aimed to study diurnal variation of DO in water in different factors by controlling algae density,temperature, sediment and biomass respectively. By linear regression analysis, we hope to find out the correlation between the factors and the dissolved oxygen, and calculated quantitative relationship between each factor and DO in certain range, and then explore the effect of each factor on change of DO in water.As an important primary producer of water, the growth and metabolism of algae is very sensitive to the change of dissolved oxygen in water. Algae released oxygen by photosynthesis at day(DO increase) and consumed oxygen at night(DO decrease), resulting in greater DO difference in water between day and night. DO in water varied regularly with change of light intensity, that is to say, with the increase of light intensity, the photosynthesis of algae enhanced and produced more oxygen, and light intensity reached maximum at a moment in the afternoon,when DO in water also reached maximum; on the contrary, with the decrease of light intensity,DO reduced. When the algae density in the water body is in a certain node, oxygen producing by photosynthesis and oxygen consuming by respiration will reach dynamic equilibrium, and the DO diurnal variation of the water body is not significant, which is basically maintained, at a certain level.Aquatic organisms consume oxygen in water to achieve metabolism(such as respiration,motion, maintaining body temperature). The results indicated that biomass had a significantly negative relationship with DO, and DO values were reduced with increasing biomass, when biomass were too much, it would lead to death. By Spearman correlation analysis, the coefficientbetween biomass and DO was r =-0.820(p = 0.001 < 0.05), and linear correlation equation was Y(DO)= 6.310- 0.194X(Biomass)(R2 = 0.793).The effect of water temperature on DO is mainly about solubility of oxygen in water. The results showed that water temperature and dissolved oxygen were significantly linearly negatively correlated, and DO values were raised with the drop of water temperature. By Spearman correlation analysis, the coefficient between temperature and DO was r =-0.690(p =0.013 < 0.05), and linear correlation equation was Y(DO) = 10.745- 0.204X(Temp)(R2 = 0.648).Microorganisms and organic matter in the sediment are the main factors of oxygen consumption in water. Theoretically, with the increase of the sediment, the more dissolved oxygen are consumed in water, however in the experiment, condition was not so. Adding sediment into water by three groups, result showed that all do values were decreased, but groups with less sediment were consumed more oxygen than more ones. Reason was that with sediment’s increase, water was in anaerobic environment and oxygen consumption rate was reduced.更多还原