Within the ocean monitoring program integrated studies are carried out in the North Atlantic and the Baltic Sea. This is accomplished by outfitting commercial vessels with scientific instrumentation (Volunteer Observing Ships, VOS). On board these vessels instruments are installed in order to measure CO2 in the surface water and other relevant physical (temperature, salinity) and biogeochemical (nitrate, oxygen) parameters.
Recent results of a coordinated observation system for determining the CO2 gas exchange in the North Atlantic, show how surprisingly strong the gas exchange can change from one year to another. Despite this large variability the annual gas exchange for the whole basin could be determined accurately by means of oceanic monitoring network VOS lines. This network has been set up within the EU projects and CAVASSOO and CARBOOCEAN.