CONTROLS OF CO2 SOURCES AND SINKS IN THE EARTH SCALE SURFACE OCEAN: TEMPERATURE AND NUTRIENTS

The ocean has prominent regions where disequilibiump ersists on an annuala verageb etween CO2 in the surface water and the overlying atmosphere. This paper examines several of these regions using models in which CO2 cycles in a steady state, where sources (ocean outgassing) and sinks ( ingassing) are in balance. The relative strengths of surface temperatures and surface nutrients, the two main contributors to the source and/or sink properties, are quantified in each model. Models with two ocean surfaces indicate that the sink in the north Atlantic and the sources in the equatorial Atlantic and Pacific are all dominated by the global temperature pattems. Several ocean models with three surface zones explore alternatives for forming the earth's strongest source, in the equatorial Pacific, a particularly interesting region because temperature and nutrients clearly reinforce each other. Data show that a model to explain the control factors upon the equatorial Pacific source must extend to over 30% of the global ocean to reach the nearest counterbalancings ink between 40 degrees S and 50 degrees S. From the analyses of the equatorial Pacific, the conclusion is that temperature control is responsible for certainly more than 50%, and probably closer to 70%, of the CO2 outgassing with the balance coming from the Earth surface nutrient structure.