Vertical Fluxes of Carbon and Nitrogen at Station ALOHA

Jim Christian

Abstract

The deep ocean is a potential sink for anthropogenic CO₂ on timescales of decades to centuries, and the net flux of CO₂ into the surface ocean is driven by transport of carbon across the thermocline. In a nitrogen-limited system, net downward transport of carbon occurs only if the C/N ratio in the downward flux is greater than in the upward flux. The HOT data provide a unique opportunity to examine these processes because we have measured all of the major pools of C and N (dissolved/particulate, organic/inorganic) as well as vertical fluxes. These data will be used to test the hypothesis that there is a net vertical flux of C out of the surface ocean comparable in magnitude to the atmosphere-ocean flux of CO₂.