Surface water ρCO2 was observed continuously from January 2003 to November 2006 at Marian Cove,King George Island,Antarctica,using the flowing ρCO2 system at the King Sejong Station.During the observation period,temperature,salinity,nitrate + nitrite,and chlorophyll a (chl a ) ranged fron –2.25oC,31.0 – 34.5,20 – 30 μM,and ~10μg L-1,respectively.Surface ρCO2 values fluctuated from 300 to 480uatm,with relatively low values in summer and relatively high values in fall.Air ρCO2 ranged from 365 – 378μatm.Thus,the ΔρCO2 (air ρCO2 minus seawater ρCO2) ranged from -80 to 100 μatm during the study period.The study site (Marian Cove) acted as an atmospheric CO2 sink in summer but served as a weak source of CO2 to the atmosphere during other seasons.Daily averaged values of ρCO2 were negativity correlated with temperature and positively correlated with chl a,suggesting that elevated biological production in summer resulted in strong CO2 uptake.However,CO2 variation within a day was correlated with variation in temperature and tides.Tidal turbulence in the coastal ocean influences the sea-to-air gas transfer by increasing vertical mixing and gas transfer velocity (Hahm et al.2005).Therefore,we recommend further long-term CO2 monitoring together with the observation of other environmental factors,including tidal turbulence as well as sea-ice and meltwater effects.This research will be crucial for understanding the factors that affect CO2 variation in an Antarctic coastal environment and for validating the role of Antarctic CO2 in the global cycle.This study presents preliminary,yet novel,results of high-resolution CO2 monitoring along the Antarctic coast and begins to investigate which factors control the season and daily variation in surface water CO2 of an Antarctic coast.