高原深水湖泊抚仙湖溶解氧分层特征及驱动因素  

Stratification Characteristics of Dissolved Oxygen and Its Driving Factors in a Typical Plateau Deep Lake

作　　者：张秀锦 牛远[1] 吴亚丽 王平 段友爱 余辉[1] ZHANG Xiujin;NIU Yuan;WU Yali;WANG Ping;DUAN Youai;YU Hui(State Environmental Protection Key Laboratory for Lake Pollution Control,Institute of Lake Ecology Environment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;Yunnan Provincial Centre for Ecological Environmental Monitoring,Kunming 650034,China)

机构地区：[1]中国环境科学研究院湖泊生态环境研究所,湖泊水污染治理与生态修复技术国家工程实验室,北京100012 [2]云南省生态环境监测中心,云南昆明650034

出　　处：《环境科学研究》2024年第5期1006-1014,共9页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2022YFC3204002)。

摘　　要：深水湖泊特有的“表水层-温跃层-深水层”的热力学分层结构,决定了湖内溶解氧(DO)的垂直分布和混合交换,影响着湖内生态系统的健康.然而,目前对于深水湖泊耗氧与复氧过程及其驱动因素的研究还不够深入,尤其对高原深水湖泊的研究更为缺乏.为此,本研究于2021年1月-2022年2月进行了分层采样和逐月监测,探究了典型高原深水湖泊抚仙湖的溶解氧分层特征及驱动因素.结果表明:①抚仙湖热力学分层周期分为两期,即分层期和非分层期.分层期为3月下旬至11月上旬,混合期为11月下旬至3月上旬.②在湖泊热力学分层的驱动下,湖内DO垂直分层明显.表水层DO浓度年内变化范围为6.67~8.64 mg/L,而温跃层和深水层DO最低浓度分别可降至3.15和1.26 mg/L.③抚仙湖不同水层DO浓度变化的驱动因素及效应占比不同.表水层DO受到水温、光合作用、大气复氧和气象条件的综合影响;温跃层DO主要受分层强度和浮游植物生命活动的影响;深水层DO主要受分层强度、有机质沉降分解、沉积物有机质分解的影响.研究显示,抚仙湖底层水体长期处于厌氧状态,由此带来的湖泊生境的改变以及底部营养盐释放的风险值得关注.The thermal stratification structure of‘epilimnion-thermocline-hypolimnion’determines the vertical distribution and mixing exchange of dissolved oxygen(DO)in deep lakes,affecting the health of lake ecosystems.However,studies on the replenishment and consumption of DO and its driving mechanism are still lacking,especially in plateau deep lakes.Therefore,through stratified sampling and monthly monitoring of Fuxian Lake,a typical plateau deep lake,from January 2021 to February 2022,the stratification characteristics and driving factors of DO were explored.The results showed that:(1)The thermodynamic stratification cycle of Fuxian Lake was divided into two periods,namely stratification period and non-stratification period.The stratification period was from late March to early November,and the mixing period was from late November to early March.(2)Driven by the thermodynamic stratification,the vertical stratification of DO was obvious.In the epilimnion,the concentration of DO was relatively sufficient,with a range of 6.67-8.64 mg/L.However,in the thermocline and hypolimnion,the minimum concentration of DO could be reduced to 3.15 and 1.26 mg/L,respectively.(3)The driving factors affecting DO distribution in vertical profiles were different.In general,water temperature,photosynthesis,atmospheric oxygen exchange and meteorological conditions all affected DO fluctuation in epilimnion.The stratification intensity and phytoplankton life activities were the main factors affecting DO within the depth of thermocline.The stratification intensity,sedimentation and decomposition of organic matter and sediment release were the main factors driving the consumption of DO in hypolimnion.This study showed that the bottom water of Fuxian Lake was always in an anaerobic state.Therefore,the impact on the lake habitat and the risk of nutrient release in the hypoxic environment are worthy of attention.

关 键 词：高原深水湖泊 抚仙湖 溶解氧(DO) 驱动因素 混合模式 富营养化 

分 类 号：X524[环境科学与工程—环境工程]