ORGANIC-MATTER IN LARGE TURBID RIVERS - THE HUANGHE AND ITS ESTUARY

To investigate the pattern of organic matter transport in large turbid rivers, we analyzed water samples from the Huanghe river and its estuary during the dry and wet seasons in 1987 for particulate and dissolved organic carbon (POC and DOC), sugars and amino acids. The dry season was characterized by POC contents of 1.5-9.1% of the total suspended matter (TSM), and particulate sugar and amino acid concentrations of 140-490-mu-g l-1 and 560-1270-mu-g l-1 respectively. Of total POC, 24-46% was contributed by amino acids and sugars. During the wet season, POC contents were 0.6-1% of TSM; concentrations of sugars and amino acids were, respectively, 290-8660-mu-g l-1 and 690-11 560-mu-g l-1, and their contributions to POC varied from 9 to 18%. DOC varied from 3.2 to 4.5 mg l-1 during the dry season and from 5.0 to 8.5 mg l-1 during the wet season- The corresponding concentrations of dissolved sugars and amino acids were, respectively, 50-260-mu-g l-1 and 20-530-mu-g l-1 during the dry season and 150-500-mu-g l-1 and 75-720-mu-g l-1 during the wet season. Together they contributed 1.1-6.2% to DOC during the dry season and 1.6-9.4% during the wet season. The spectral distribution of sugars and amino acids suggests transport of relatively fresh, autochthonous organic matter during the dry season, and of microbially reworked, soil-derived organic matter during the wet season. Thus, despite its highly turbid nature, the organic matter transport characteristics of the Huanghe are similar to those previously reported for other major world rivers. Annually, the Huanghe transports 6.1 X 10(12) g of POC and 0.2 X 10(12) g of DOC, of which about 17% and 3.0% respectively can be accounted for by sugars and amino acids.