[Distributions of dimethylsulfide and dimethylsulfoniopropionate and influencing factors in the East China Sea and the Southern Yellow Sea during the winter].

The concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) were measured in situ in the East China Sea and the Southern Yellow Sea during December 2011 and January 2012 to study their horizontal distributions and influencing factors. Besides, the size distribution of DMSPp and the sea-to-air flux of DMS were also investigated. The concentrations of DMS, dissolved DMSP (DMSPd) and particulate DMSP (DMSPp) ranged from 0.58 to 4.14, from 0.37 to 7.86 and from 4.29 to 25.76 nmol x L(-1), respectively, with the average values of (2.20 +/- 0.82), (2.12 +/- 1.66) and (11.98 +/- 6.23) nmol x L(-1). In addition, significantly positive correlations were found between DMS, DMSPp and chlorophyll a, and their diel variations followed the same trend, implying that phytoplankton biomass might play an important role in controlling the production and distributions of DMS and DMSP. A negative correlation was found between DMSPd and total bacterial abundance, probably because DMSPd was transferred into DMS under the action of DMSP lyase released from bacteria. Moreover, the larger nanophytoplankton (5-20 microm) contributed to the vast majority of Chl-a and DMSPp in the study area. The sea-to-air fluxes of DMS during the investigation were estimated to be from 0.61 to 25.52 micromol x (m2 x d)(-1), with an average of (8.30 +/- 5.92) micromol x (m2 x d)(-1).