周村水库季节性热分层消亡期水质响应特性

以我国北方代表性水库周村水库为研究对象，研究分层消亡对水库水质污染的影响。于2014年10月-2015年1月对周村水库热分层减弱消亡期理化指标和浮游植物进行连续监测。结果表明：秋季水体分层结构的破坏，对水库水质污染与水环境的变化影响显著。随着秋季气温的下降，温跃层厚度减小，混合深度增大。分层破坏期间，水库底部仍处于厌氧状态，大量污染物（如锰、氨氮、硫化物等）从沉积物中释放出来。随着混合深度的增加，蓄积底部水体中的还原性污染物向上迁移，大量消耗水中溶解氧，导致水质恶化、嗅味异常、鱼类大量死亡。同时，大量的藻类可利用营养盐通过水体对流进入上层水体，但由于秋冬季水温和光照强度较低，并未引起浮游植物密度的增长。

Response of water quality of Zhoucun reservoir during the disappearance of seasonal thermal stratification

The Zhoucun reservoir, located in northern China, was investigated to study the effects of stratification destruction on the quality of water pollution. The physical, chemical, and phytoplankton indexes were continuously monitored from October 2014 to January 2015. The results showed that the subdued thermal structure had a significant effect on the water environment. Along with the decreasing air temperature in the autumn, the thermocline thickness decreased and the mixing depth increased. During the stratification-weakening period, the bottom water remained anaerobic, and the contaminants (such as manganese, ammonium, and sulfide) released greatly from the sediment. In addition to the increase in mixing depth, the reducing pollutants migrated upward, consuming the dissolved oxygen in the surface water and leading to water quality deterioration, odor, and other problems, such as dead fish. In addition, the phytoplankton nutrient-availability content increased in the surface water. In spite of the high nutrient level, the algal cell density did not increase because of the low temperature and light intensity.