Riverine sources and estuarine fates of particulate organic carbon from North China in late summer

Suspended sediments from three North China estuaries, the Luanche, Shuangtaizihe and Yalujiang, were collected during August in 1991-93 to determine the organic carbon concentrations. Distributions of particulate organic carbon (POC) demonstrate distinctive features in each estuary: a rather simple dilution of the terrigenous population by organic poor particles for the Luanhe, relatively low and stable levels of POC in the Shuangtaizihe, and an important contribution from the organic pool at the turbidity maximum zone of the Yalujiang. Comparison of POC between large Chinese rivers shows a general trend of a rapidly decreasing POC content with increasing amounts of suspended sediments. On a logarithmic scale, a negative relationship between the concentration of POC and total suspended sediment has been found for large Chinese systems.