Temporal and Spatial Distributions of Organic Carbon in the Huanghe(Yellow) River

We examined organic carbon(particulate and dissolved) throughout the main stream of the Huanghe River from 2003 to 2009.The river is characterized by TSS(total suspended substances),POC and DOC concentrations of 91.42～8188,0.65～24.20 and 1.57～4.77 mg/L,and POC%(POC content in TSS) of 0.44%～2.21%,respectively.The seasonal distributions of organic carbon are strongly connected with discharge: POC is mainly influenced by erosion with runoff and DOC is affected by flush effect or dilution in different seasons.Compared with the main stream of the river,phytoplankton contributed much more to organic carbon in the reservoirs where DOC/POC varied from 6.64 to 12.00,indicating that organic carbon is dominated by DOC.Substantial POC load is retained in the reservoirs due to precipitation.However,considerable amount of organic carbon would be exported during the SW period when POC is the main form in organic carbon with DOC/POC value between 0.01～0.47.