This research focuses on identifying spatial and temporal variationsof the carbon dioxide system in the surface seawater of Tartouscityduring the period betweenspring and summer 2015.In Addition to the extent influenced by some hydrological properties of water (temperature and salinity) and the impact all of this on the pH of marine water values. The results showed low partial pressure of the carbon dioxide in seawaters (PCO2 sea) in the summercompared with spring, which is reflected on the air-sea flux values (FCO2), where CO2 released from surface seawater to the air in summer and incontradiction of that in the spring (0.0632mmol /m²/ day and -0.0715 mmol /m²/day, respectively). In spring, low temperature and salinity of the water (22.707-22.727C and 37.605-37.765‰ respectively), in addition to increased biological activity contributed in increasing the absorption of CO2 from the water.These leading to a decrease PCO2 sea (409.0- 429.5μatm) associated with low concentrations of all of the total inorganic carbon (2229.5- 2242.5μmol/kg) and total alkalinity (2588.873-2590.9μmol/kg). and as a result the surface sea waters become a reservoir of dioxide carbon atmospheric. In the summer, the rise in temperature and salinity of surface seawater (28.85- 29.60Cand38.15-38.60‰, respectively) and reduced biological activity all contributed to the decrease dissolved CO2 values and increase of PCO2 sea(437.5 - 453.5μatm) associated with increasing concentrations of each of the total inorganic carbon (2267.9 - 2296.0μmol/kg) and total alkalinity (2739.6 -2741.2μmol/kg).In this way the surface sea water is source of carbon dioxide to the atmosphere.