Three algal communities cultured from inocula sourced from geographically distinct locations within the continental United States were maintained under identical sequencing-batch growth conditions in photobioreactors and sampled over 82 days. Communities were sequenced via both V4 and V8-V9 18S rRNA gene sequencing. Mothur and R were used to analyze sequencing data and to describe and compare community dynamics within and between communities. This project includes both mothur and R script files used to analyze the data