Table 1: Steps followed for validation of denoised sequences obtained from Research and Testing laboratory.

Steps to validation of sequences Sequences
# %
Initial total number of sequences denoised following the R&T processing. 11.717 100
After checking for chimeric sequences 9.891 84,4
After checking for presence of ambiguous nucleotides 9.061 77,3
After checking sequences coding for nosZ gene 8.460 72,2
After checking for sequences <350 bp 6.740 57,5
After eliminate duplicate of sequences 6.697* 57,1

* A total of 6.697 sequences were validated for the analysis: 3.184 sequences for Lozania station (L6), 2.890 sequences for Tomogó station (T9) and 623 sequences for Isla del Sol station (IS7).