UNDERSTANDING AND PREDICTING THE IMPACT OF AGRICULTURE ON THE ENVIRONMENTAL INTEGRITY OF MANAGED WATERSHEDS
Location: Water Quality and Ecology Research
Title: Potential for phosphate mitigation from agricultural runoff by three aquatic macrophytes
Submitted to: Water, Air, and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2012
Publication Date: August 1, 2012
Citation: Tyler, H.L., Moore, M.T., Locke, M.A. 2012. Potential for phosphate mitigation from agricultural runoff by three aquatic macrophytes. Water, Air, and Soil Pollution. 223(7):4557-4564.
Interpretive Summary: Best management practices are needed to help reduce the potential harmful effects of nutrients in agricultural runoff before they contribute to downstream eutrophication. Management practices such as constructed wetlands and vegetated ditches rely on plants to help mitigate nutrients from the runoff water. This study examined three plant species common to wetland and ditch habitats and found they were able to reduce the amount of phosphate in runoff water significantly following a simulated storm event. This research is critical in order to afford better design and community composition of vegetated aquatic systems that serve to filter out nutrients in storm runoff.
Phosphate from agricultural runoff is considered a contributor to eutrophication. Three aquatic macrophyte species, Leersia oryzoides, Typha latifolia, and Sparganium americanum, were investigated for their phosphate mitigation ability. Mesocosms were exposed to flowing phosphate enriched water (10 mg L-1) for 6 h, left stagnant for 42 h, and then flushed with non-nutrient enriched water for an additional 6 h to simulate storm flushing. Both L. oryzoides and T. latifolia decreased the load of dissolved phosphate (DP) in outflows by greater than 50%, significantly more than S. americanum, which only decreased DP by 15±6% (p = 0.002). All treatments decreased concentrations inside mesocosms by 90% or more after one week, though the decrease occurred more rapidly in T. latifolia and L. oryzoides. By discovering which species best mitigate nutrients in agricultural runoff, planning the vegetative community composition of drainage ditches and constructed wetlands can be improved for optimal remediation results.