Burrowing aquatic invertebrates alter rates of phosphorus release from aquatic sediments in agricultural drainage ditches

Agricultural drainage ditches receive large inputs of nutrients such as phosphorus, which may be delivered to downstream bodies of water and contribute to eutrophication of coastal and estuarine environments. Therefore, retention of excess phosphorus within ditch sediments would help to improve water quality downstream. Current research on phosphorus retention within ditch sediments has focused on physical and biogeochemical processes as they relate to hydrology, water and sediment chemistry, and soil microbes, but have largely ignored influences of aquatic macrofauna. Bioturbation by burrowing aquatic invertebrates can alter rates of biogeochemical cycles and alter rates of flux for dissolved species across the sediment-water interface. Sediment and water mesocosms were used to test the effects of different species of burrowing aquatic invertebrates on the uptake and release of dissolved phosphorus from overlying water. Results from these experiments show that certain species of burrowing invertebrates may alter rates of phosphorus release from aquatic sediments within drainage ditches, and could change the ability of ditches to retain phosphorus bound to sediments.