Characteristics of bacterial community structure and diversity in overlying water and sediments with Lotus in the Baiyangdian Lake, China

Bacterial communities in water and sediments are important decomposers of lake ecosystem. However, the differences in bacterial community structure and biodiversity in overlying water and sediments covered by aquatic plants such as Lotus in lake ecosystems are still poorly understood. Here we collected paired overlying water and sediments in the Baiyangdian (BYD) Lake to explore their characteristics of bacterial community. Our results showed that bacterial diversity indices such as Sobs, Shannon, Simpsoneven and Phylogenetic diversity in sediment samples were significantly higher than those in overlying water samples, which were mainly affected by ofloxacin (OFL), dissolved oxygen and pH in the overlying water, while norfloxacin (NOR), OFL and sulfapyridine (SPD) in sediments. Dominant phyla across all overlying water samples were Actinobacteriota (36.65%), Proteobacteria (29.12%) and Patescibacteria (17.01%), while Proteobacteria (20.97%), Chloroflexi (19.56%) and Actinobacteriota (13.37%) in all sediment samples. Source Tracker results showed that about 6.59 ± 1.9% of the variations in bacterial community in sediments could be attributed to the contribution of the overlying water bacterial community, which is higher than that of sediments to the overlying water bacterial community. The dominant factors shaping the bacterial communities in the overlying water were NOR, dissolved organic carbon (DOC) and total phosphorus, while in sediments were NOR, OFL and DOC. It is suggested that antibiotics (especially NOR) may have a substantial effect on bacterial community rather than interaction of environmental compartments (overlying water and sediments), and would help to improve the understanding of bacteria transfer and coalescence in a shallow lake ecosystem.