16S Amplicon sequence variants (ASVs) data of NEREA Augmented Observatory

Cleaned raw 16S paired-end sequences were imported into the QIIME2 pipeline v. 2022.2.0. Leftover primers and adapters’ sequences were removed through cutadapt. The amplicon sequence variants (ASV) table, which represent true biological sequences within each sample, was generated using the denoised-paired method including truncation, denoising, dereplication, and chimera filtering of the DADA2 (Divisive Amplicon Denoising Algorithm 2) plugin inside QIIME2. Default parameters were used with the exception of the forward and reverse sequence length (--p-trunc-len-f and --p-trunc-len-r), that were set to 220 and 180, respectively. For taxonomy classification, the V4-V5 region were extracted from the pre-formatted reference sequences and taxonomy file build on the SILVA 138 99% OTUS database and the vsearch v. 2.6.2 global alignment implemented in QIIME2 was used.