effects of flow on phosphorus uptake by periphyton

Everglades restoration includes construction of six Stormwater Treatment Areas (STAs) totaling over 16,000 hectares. These filter marshes are designed to remove excess phosphorus from agricultural runoff and urban wastewater before it reaches the Everglades. Optimizing flow through these wetlands may be important in increasing the efficiency of nutrient removal and achieving lower outflow phosphorus concentrations. We measured periphyton growth and phosphorus uptake in two sets of replicated mesocosms in post-STA treatment water. Flow rates for the study were 1.0 cm s^-1 and 0.11 cm s^-1. Unique mesocosm design allowed for simultaneous control of loading rate, retention time and surface area, leaving flow rate as the single variable between treatments. Periphyton biomass accrual was 25% greater in the faster treatment. Measurements of dissolved oxygen were positively correlated with biomass accrual and there was no significant difference in the export of biomass between treatments.