泸沽湖水体溶解氧含量时空分布规律研究

Spatial-temporal Distribution of Dissolved Oxygen in Lugu Lake

该文通过资料收集与现场调查,分析了高原湖泊泸沽湖水体溶解氧的时空分布。结果表明:1999-2019年来泸沽湖水体溶解氧实测浓度范围为5.2~9.5 mg/L,年际差异不大;年内在3-4月、12-次年1月溶解氧月均值较高,分别与水生植物光合作用及气温有关,而8-9月出现较低值,主要受高气温影响;泸沽湖全湖范围内水体溶解氧含量空间上有一定差异,大致表现为南侧及湖心里务比岛附近水体溶解氧稍高,北侧稍低,主要是局部湖区水动力特性、水生植物及浮游植物群落的差异所致;由于水温分层差异显著,泸沽湖水体溶解氧存在明显垂向分层,温跃层内溶解氧含量达峰值,温跃层之上溶解氧含量垂向均匀,温跃层之下溶解氧含量随水深逐渐降低。研究结果可为泸沽湖水环境管理提供参考。

The spatial-temporal distribution of dissolved oxygen in Lugu Lake,a plateau lake was analyzed on the basis of data collection and field observation.The results showed that the varied range of the dissolved oxygen was 5.2~9.5 mg/L during the years from 1999 to 2019,with little interannual variation.The mean values of dissolved oxygen for March,April,December and January were higher than those of the other months within one year,attributed to the photosynthesis and air temperature,individually.Whereas,the lower mean values of dissolved oxygen in August and September were led by the higher air temperature.The dissolved oxygen varied with space in 2019 and 2020,with higher values in the south and the sites around the Liwubi Island of the lake center,and lower values in the north.The hydrodynamic characteristic,hydrophyte and phytoplankton have spatial variation and lead to the dissolved oxygen pattern in the lake.Due to the water temperature stratification,the dissolved oxygen also has stratification,with the largest values in the layer of thermocline,the uniform values above the thermocline,and declined values with the water depth beneath the thermocline.The results will provide help for the water environmental management of Lugu Lake.