3.1. DNA sequence data analysis
From the 452 raw files, we analysed 16.5 million V3-V4 regions, (except 13 files of V4-V5 archaea specific primer files of Wage et al.[38], Table 1) of bacterial 16S rDNA gene sequences that belong to five copepod genera, i.e. Acartia spp.,Calanus spp., Centropages sp., Pleuromamma spp. andTemora spp. After quality filtering through DADA2 package, an average of 0.1 to 7.8% of sequences was removed (Table 2), and a total of 1, 39, 87,186 sequences were used for downstream analysis.