We agree with the reviewer that we have not stressed this fact enough and have added more sentences explaining why OTUs are used and the problem: “Enormous progress happened in prokaryote taxonomy in the recent years [8,12,24]. However, the data produced with novel methodologies, such as next generation sequencing, often requires a high throughput taxonomic classification of sequences such as fixed threshold to identify OTUs. This kind of fixed numeric classifications can always only be a vague approximation to the actual structure of relatedness of organisms.”
Round 1: and Author Response The authors tested novel approach to identification of species in cyanobacteria based on 16S rRNA based on identification of barcoding gaps previously used in animals.