The ocean network of ICOS (Integrated Carbon Observation System) provides long-term observations of the ocean required to understand the present state and better predict future behaviour of the global carbon cycle and climate-relevant gas emissions. The oceanic sink currently offsets approximately 25% of CO2 emissions from human activities. Quantifying these fluxes for the Atlantic Ocean is critical for determining the European carbon budget and for accurate accounting of land fluxes. Global and subsurface measurements must also be taken into account to assess the role of the ocean in the global carbon cycle.