title: Pond 2 sediment in Zhuhai in Nov
design: The sediment microbial DNA was extracted from approximately 0.3 g of sediment using the same kit. DNA concentration and purity were evaluated using a Nanodrop 2000 spectrophotometer (Thermo Scientific, USA) and DNA integrity was evaluated using 1% agarose gels. The V4V5 hypervariable region of the 16S rRNA gene was amplified using the universal primer pair 515F and 907R (Cai et al., 2016; Huang et al., 2021) with a 12-nucleotide sample-specific barcode.