Fig 2. Change in OTUs and identified genera over the course of bioreactor monitoring.

A steep decline was observed for both OTUs and genera during the early stage of bioreactor operation. (Inset) Change in alpha-diversity with time. Although the number of OTUs did not increase during the perturbation period, populations that were in lesser abundance prior to the perturbation increased in abundance, which would be captured by the use of the Shannon-Weaver index.