Bacterial Composition and Influencing Factors in Surface and Bottom Waters of Three Major Drinking Water Reservoirs in Guiyang,Southwestern China

Reservoirs are one of the main forms of utilizing surface water resources. As the construction time of a reservoir increases, it begins to exhibit limnological responses or processes similar to those of natural lakes, including thermal stratification, light stratification, redox stratification, and dissolved oxygen stratification . Bacteria play a crucial role in various biogeochemical reactions in reservoirs (such as sulfate dissimilatory reduction, sulfide oxidation, iron and manganese cycling, organic matter degradation, methane production, and nitrate removal), functioning as "source element pumps." Changes in the physical and chemical environment of a reservoir affect the bacterial composition at different depths, and conversely, changes in bacterial composition impact the migration and transformation of elements and their compounds in the water, which can influence short-term microhabitat changes and long-term environmental evolution. Assuming that the reservoir ecosystem is in a steady state over a period, the bacterial composition and the corresponding migration and transformation of elements and compounds in the water may have characteristic fixed relationships. Understanding and clarifying this intrinsic connection could provide accurate assessments of short-term and long-term environmental evolution processes and directions, thereby aiding in the refined management of reservoir water quality.

水库是地表水资源开发利用的主要形式之一。随着水库运行年限的增长，其会逐渐呈现出与天然湖泊相似的湖沼学（limnology）响应与过程，包括热分层（thermal stratification）、光分层（light stratification）、氧化还原分层（redox stratification）以及溶解氧分层（dissolved oxygen stratification）。细菌在水库的各类生物地球化学反应（biogeochemical reactions）中发挥关键作用，涵盖硫酸盐异化还原（sulfate dissimilatory reduction）、硫化物氧化（sulfide oxidation）、铁锰循环（iron and manganese cycling）、有机质降解（organic matter degradation）、产甲烷作用（methane production）以及硝酸盐去除（nitrate removal）等，并发挥着“生源元素泵”的功能。水库物理化学环境的变化会影响不同深度的细菌群落组成（bacterial composition）；反之，细菌群落组成的改变也会影响水体中元素及其化合物的迁移转化，进而影响短期微生境（microhabitat）变化与长期环境演化。若假设水库生态系统在某一时间段内处于稳态（steady state），则细菌群落组成与水体中对应元素及其化合物的迁移转化之间可能存在特征性的固定关联。理解并阐明这一内在关联，可精准评估短期与长期的环境演化过程与方向，从而助力水库水质的精细化管理。