Wu, G.-W. and Yang, G.-P., 2013. Distributions of dissolved carbohydrates in the Yellow Sea and the northern East China Sea in early winter.

Carbohydrates are the largest identified fraction of dissolved organic carbon and play important roles in biogeochemical cycling in the ocean. Seawater samples were collected from the Yellow Sea (YS) and the northern East China Sea (ECS) during November–December 2009 to study the spatial distributions of total dissolved carbohydrates (TCHO) constituents, including dissolved monosaccharide (MCHO) and polysaccharide (PCHO). Average concentrations of MCHO and PCHO in the surface water were 11.0 and 39.8 μmol C/L, and their contributions to dissolved organic carbon (DOC) were 4.8% and 17.5%, respectively. Both MCHO and PCHO displayed similar distribution patterns; consequently, a significant correlation was found between them. However, MCHO and PCHO did not display correlation with chlorophyll a in the seawater, suggesting that phytoplankton biomass was not the sole factor controlling the distribution of carbohydrates in the study area. The riverine input had a significant influence on the distribution of carbohydrates, and therefore higher concentrations of TCHO were found near the Changjiang River mouth. The carbohydrate enrichments in the near-bottom waters were found at some stations, suggesting that there might be important sources of carbohydrate in the deep waters or bottom sediments.