【摘要】：Methane(CH_4) is an important greenhouse gas and oceans are net sources of atmospheric CH_4. The effects of environmental factors on the CH_4 variation during different phases of the spring algal blooms were examined during two cruises conducted in the Yellow Sea(YS) from February to April of 2009. During the pre-bloom period from February to March, low CH_4 saturation( 134%) was observed in the surface water, except at two nearshore stations where the CH_4 levels were above 140% in March due to mixing with the coastal water. During the bloom period, CH_4 increased obviously at two bloom-tracking stations, especially at the surface with mean saturations of 140% and 170%. The increase in CH_4 concentration/saturation is thought to be the result of in situ CH_4 production. The particulate organic carbon(POC) and chlorophyll a contents were believed to be important factors that influenced the CH_4 production. In addition, the presence of different dominant phytoplankton species and the grazing pressure may have stimulated the CH_4 production by supplying potential methanogenic substrates(such as dimethylsulphoniopropionate(DMSP)). Both the incubation data and the in situ estimations further evidenced the significant influence of the spring blooms on the CH_4 production. The calculated sea-to-air CH_4 fluxes during the bloom period were not significantly higher than those during the pre-bloom period despite the bloom-increased CH_4 saturation. This is due to the variation in physical forcing(such as wind speed), which is the main driver for determining the CH_4 flux. Finally, we estimated the annual CH_4 flux in the YS as 9.0 μmol m~(-2) d~(-1); the findings suggest that the YS is a natural source of atmospheric CH_4.