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.”
Summary: The manuscript is surely useful and, in principle, it presents a good contribution to the recent methodological trends (polyphasic approach) in cyanobacterial taxonomy, this conclusion should be the main result from this work.