European continental shelf as a significant sink for atmospheric carbon dioxide

The concentration of carbon dioxide was measured during 18 cruises in the s urface waters of the North Atlantic European Shelf (Galician sea, Gulf of B iscay, Armorican Sea, Celtic Sea, English Channel, North Sea), covering all four seasons (9 out of 12 months) at interannual scale. This is the very f irst intensive field study of continental shelves, in terms of source/sink for atmospheric CO2, which allows to integrate fluxes on an annual basis an d over a large surface area. Here we show that European continental shelves are a sink of 90-170 million tons of carbon per year, which is an addition al appreciable fraction to the presently proposed flux for the open North A tlantic Ocean (similar to 45%). The air-sea fluxes of CO2 we obtained are s imilar to those recently reported in the East China Sea, allowing us to con clude that the coastal ocean plays a considerable role in the global oceani c carbon cycle.