分层湖库溶解氧时空特性研究进展

A review of dissolved oxygen variation and distribution in the stratified lakes or reservoirs

溶解氧(DO)是湖库水质管理的关键变量之一,对维持湖库生态系统平衡至关重要。受控于湖库生态、生物地球化学和物理过程的相互作用,湖库DO对气候、地理、富营养化、有机污染、水文及负荷的输入等环境压力反应敏感。随着监测技术的提高、实验分析的多样、模型工具的完善,溶解氧垂向分层机理研究也更加深入。分层湖库的表面温水层因大气复氧、光合作用等的影响DO饱和程度高,变温层DO与受透明度影响的浮游生物呼吸与光合作用、水平和表层等外部物质输入、有机物沉积过程分解等机制有关,DO垂向形态多样,其中变温层DO极小值广泛存在且成因复杂。滞温层缺氧与沉积物、初级生产力、外部输入湖库大小等有关,通过数据分析和模型手段,滞温层DO演变过程得到较好的解释。由于分层湖库影响DO时空分布的因素众多,个别因子或经验公式分析,很难对湖库DO现象做出全面精确的描述,基于机理及过程的数值模型是DO研究中必不可少的工具。针对分层湖库越来越普遍的缺氧现象,为水质和生态环境的改善提出合理的科学措施,提高水库管理,采用原位监测、经验参数、公式和数值模型等手段,揭示湖库溶解氧的演变机理,是需要继续深入研究的课题。

Dissolved oxygen(DO),one of the key variables in water quality management,is essential for the ecosystem functioning of these lentic ecosystems.Due to the interactions of lakes,ecology,biogeochemistry and physical processes,DO reacts highly sensitive against environmental stressors like climate change,geography,eutrophication,organic pollution,and hydrology and loads process.With the improvement of monitoring technology,deeper data analysis,and modeling tools,the research on vertical delamination of dissolved oxygen has become more in-depth.The DO is high saturated in the epilimnion due to atmospheric oxygenation,photosynthesis,while metalimnetic oxygen is varying by respiration,photosynthesis,advection,vertical diffusion organic deposition and so on.Metalimnetic oxygen minima(MOM),a popular phenomenon in lentic systems,is more complicated and still no fully explained.The hypolimnetic DO depletion is related to sediments deposition,primary productivity,and income loads,and it is intensively studied and well predictable.Since the temporal and spatial distribution of DO is influenced by lots of factors in the stratified lentic system,it is difficult to make a full and accurate description of the DO phenomenon based on the individual factors or analysis or simple empirical formulas.Processes based numerical models are the indispensable tools for DO research.The hypoxia phenomena in stratified lentic water are more in response to the increasingly widespread hypoxia phenomena in stratified lentic system,the scientific measures and reasonable reservoir management should be put forward to improve the water quality and ecological functions.Applying the high-resolution monitoring technique,empirical methods and numerical models,the mechanism of oxygen dynamics is still a subject that needs further study.