RAIN FALLING ON THE OCEAN SURFACE ALTERS SEA SURFACE SALINITY (SSS) AND THIS IN TURN COULD ALTER THE SEA SURFACE PARTIAL PRESSURE OF CO2 (PCO2) DUE TO ADDITION OF WATER WITH DIFFERENT CONCENTRATIONS OF TOTAL ALKALINITY AND DISSOLVED INORGANIC CARBON (DIC) AND DUE TO CHANGES IN SEA SURFACE TEMPERATURES (SST). THE CHANGE IN SEA SURFACE PCO2 WOULD ALTER THE AIR-SEA PCO2 GRADIENT LEADING TO CHANGES IN CO2 FLUXES WITH IMPLICATIONS FOR ANTHROPOGENIC CO2 UPTAKE BY THE OCEAN AND ULTIMATELY GLOBAL CLIMATE. THE PROPOSED EFFORT WILL EXAMINE THE RELATIONSHIP BETWEEN SEA SURFACE SALINITY AND SURFACE OCEAN PCO2 USING MEASUREMENTS OF DIC PH AND PCO2 MADE DURING SPURS-2 FROM BOTH THE SALINITY SNAKE AND FROM THE SHIP S UNCONTAMINATED SEAWATER INTAKE. BECAUSE THERE IS BOTH A LAG AND A DILUTION OF THE PCO2 SIGNAL IN THE UNDERWAY PCO2 ANALYSIS SYSTEM WE WILL EXAMINE WHETHER IT IS BETTER TO DETERMINE PCO2 FROM MEASUREMENTS OF DIC AND PH USING THE APPROPRIATE CARBON SYSTEM DISSOCIATION CONSTANTS AND TO MAKE THOSE CALCULATIONS ACCORDINGLY. IN DETERMINING THE RELATIONSHIP BETWEEN SSS AND PCO2 WE WILL ALSO TAKE INTO ACCOUNT THE CHANGES IN PCO2 DUE TO CHANGES IN SST. THE ULTIMATE GOAL OF THIS PROPOSAL IS TO PRODUCE A DATASET THAT COULD BE USED IN CONJUNCTION WITH THE OTHER STUDIES FROM SPURS-2 IN PARTICULAR THOSE EXAMINING THE EFFECT OF RAINFALL ON THE MAGNITUDE AND PERSISTENCE OF CHANGES IN SSS TO DETERMINE HOW RAINFALL WILL CREATE OFFSETS IN PCO2 BETWEEN THE SEA SURFACE AND THE BULK MIXED LAYER IN ORDER TO DETERMINE THE POTENTIAL CHANGES IN LOCAL AND GLOBAL AIR-SEA CO2 FLUXES. THE PROPOSED WORK WILL HELP ADDRESS RESEARCH QUESTION #2 OF THE SPURS-2 SOLICITATION: HOW WILL THE OCEAN RESPOND TO CHANGES IN THERMAL AND FRESHWATER FORCING ASSOCIATED WITH A CHANGING CLIMATE?