Carbon isotopic composition and flux of particulateorganic matter in the Changjing River

Abstract-Particulate organic carbon (POC) and its isotopic composition were measured monthly in the Changjiang River (at Sta.Datong) for a whole year.It shows that their seasonal distribution has an obvious change and is similar to that of the Huanghe River.The annual weighted mean of POC δ13C values of the Chanejiang River is almost the same as that of the Huanghe River.Based on the data of runoff and sediment load measured daily and POC concentration measured monthly the POC flux at Sta.Datong was estimated.The flux value at Datong may be considered approximately to be the POC flux of the Changjiang River discharging into the sea.The POC flux of the Changjiang River is slightly larger than that of the Huanghe River.