The study site is located on the Open Grounds Farm in Carteret County, NC which is located east of Beaufort, North Carolina. The farm is located in the Albermarle-Pamilico Estuarine system, a breeding ground for a wide variety of finfish and shellfish and important habitat for many birds and animals. The farm is a 44,000 -acre row crop operation. Each year, about 13,000 acres of corn, 13,000 acres of soybeans and 4,000 acres of winter wheat are planted. A portion of the farm runoff drains into headwater creeks of the South River. The South River is a tributary of the Neuse River estuary, which is part of the Pamlico Sound estuarine complex. The South River is approximately 13 km long and 2 meters deep. The upper portion of the river is bordered by irregularly flooded marsh (Juncus roemerianus), which is typical of estuarine systems in the southeastern United States. The South River exhibits estuarine circulation and salinity averages about 12 ppt.