Carbonate system distribution south of the Canary Islands in spring 2000

Abstract

The measurement of the surface molar fraction of CO₂ (atmosphere and sea water) and water column pH_T, total alkalinity, A_T, nutrients and oxygen were carried out in spring 2000 at the European Station for Time Series in the Ocean at the Canary Islands (ESTOC) and in the area located south of the Canary Islands. The significant eddy field strongly affecting the pattern of the chemical and carbonate system variables is presented and discussed. A mixing model based on the thermohaline properties of the water masses was established. The model explained over 97% of the variability found in the distribution of the chemical variables. Intermediate waters to the south of the Canary Islands show a high contribution of Antarctic waters with about 5% of pure Antarctic Intermediate Water. Moreover, the surface structure affected the atmosphere-ocean carbon dioxide exchange, making the area act as a CO₂ sink taking up 9.1 mmol m^-2 week^-1, corresponding to 0.03 Mt of CO₂ which were taken up by the area in a week at the end of March 2000.