Importance of Phaeocystis blooms in the high-latitude ocean carbon cycle

Abstract

THE Greenland Sea is particularly important to the world ocean circulation, and potentially to carbon dioxide exchange between the ocean and atmosphere, because it is an area of surface convergence and deep-water formation^1–3. Previous investigations indicate that biological productivity is low^4,5 in this area, especially in waters remote from the ice edge. During April and early May 1989, however, we observed the development of a massive bloom of the colonial prymnesiophyte Phaeocystis pouchetii across much of the Greenland Sea. From measurements of the rate of removal of nitrate from surface waters, we calculate that the average regional new production was about 40 g C m⁻² during the 35-day period of our observations. This rate of new production is approximately equal to that observed in other hyperproductive polar regions, such as the Bering Sea and the Bransfield Strait. Because Phaeocystis blooms seem to be frequent and widespread in polar oceans^4,6, our results suggest that the Greenland Sea may be a larger sink of atmospheric carbon dioxide than has been previously thought.