Formation of particulate organic carbon in water from a southeastern swamp‐stream1

The rate of particulate organic carbon (POC) formation in water from a small North Carolina swamp‐stream, low in ionic strength but high in dissolved organic carbon (DOC), was low. Mean POC formation rate, expressed as DOC utilization, was about 0.2% of DOC per day and was primarily the result of microbial activity. When Ca2+ and Hg2+ were added to swamp water, and when swamp water and seawater were mixed, the rate of POC formation increased as a result of a rapid physiochemical flocculation process. Although the DOC load of rivers and streams of the southeastern U.S. represents a substantial energy input to estuarine regions, these results indicate that only about 25–30% of it is transformed through flocculation to a form more readily retained and utilized within the estuarine system. The remainder may be transported to the sea.