effects of flow on the taxonomic composition of Everglades periphyton

Analysis of the relationship of velocity to taxonomic composition of periphyton-based stormwater treatment areas, in conjunction with other metrics, is a valuable tool for evaluating the phosphorus removal efficiency of this Everglades restoration advanced treatment technology. Periphyton taxonomic composition, biomass, water and tissue total phosphorus (TP), pH, and temperature were analyzed in three slow velocity (0.22 cm s-1) and three fast velocity (2.0 cm s-1) mesocosms. Loading rate, retention time and surface area were kept constant, with velocity the single variable between treatments. There was no significant difference in taxonomic composition, water TP, tissue TP, or temperature between the slow and fast treatments. However, dominant eutrophic and oligotrophic indicator genera exhibited significant and consistent changes in relative abundance related to location along the treatment path. Biomass accrual was 30% greater in the fast treatment and TP uptake was positively correlated with increased velocity.