Does the ocean take carbon dioxide out of the atmosphere or release CO2 into it?
Globally the ocean is a sink for atmospheric carbon dioxide because the global average partial pressure of CO2 in the surface ocean is less than that of the overlying atmosphere. Therefore carbon dioxide goes into the ocean. Mixing is very rapid in the atmosphere, so the amount of carbon dioxide, known as partial pressure, is fairly uniform throughout the globe. By contrast, the ocean mixes much more slowly and the partial pressure of carbon dioxide varies considerably in space and time. Regions that absorb atmospheric carbon are known as sinks, and regions that release it to the atmosphere are known as sources. Approximately 92 x 1015 grams of carbon enter the ocean each year and approximately 90 x 1015 grams of carbon go from the ocean to the atmosphere, leading to a net flux of carbon from the atmosphere to the ocean of approximately 2 x 1015 grams of carbon per year.
