| Abstract: | The distribution and chemical properties of colored dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea during December 2011-January 2012 were investigated. The input of freshwater and biological activities had an evident influence on the CDOM levels(characterized by the light absorption coefficient at the wavelength of 355 nm a_(355)) in the study area. The spatial distribution of CDOM levels displayed a gradually decreasing trend from the coastal waters(0.37 m~(-1)) to the open sea(0.18 m~(-1)). The spectral slope ratio(the slope ratio S_R defined as S_(275-295):S_(350-400)) during the cruise was correlated with salinity, and exhibited a large variation from inshore(average of 2.515) to offshore sites(average of 5.327) compared with the distribution of a_(355). The values of S_R were related to CDOM molecular weight(MW). The a_(355), S_R, and chlorophyll a in 37 samples collected from the surface microlayer were significantly correlated with those in the corresponding subsurface water samples, implying a strong exchange action between the microlayer and bulk water. The a_(355) and S_R of CDOM exhibited significant microlayer enrichment, with mean enrichment factors(EFs) of 1.72 and 1.62, respectively. |
