To compare the bacterial diversity among samples from different depth and different seasons, the PCR-amplified 16S rRNA genes of 189 water samples and 11 sediment samples were profiled by denaturing gradient gel electrophoresis (DGGE). Based on the DGGE results and physicochemical parameters of Lake Vechten, 51 samples from the water column and 4 samples from the sediment were selected for 16S rRNA gene amplicon sequencing (Table S3). Sequencing was performed on an Illumina MiSeq system by Research and Testing Laboratory (Lubbock, Texas, USA). The details of amplicon sequencing and operational taxonomic unit assignments were described in a previous study (Diao et al. 2017 (link)).