BIOLOGICAL PRODUCTIVITY DETERMINED FROM OXYGEN MASS-BALANCE AND INCUBATION EXPERIMENTS

The flux of metabolic products from the surface ocean regulates the carbon dioxide concentration in the atmosphere on time scales shorter than millennia and is central to our perception of how the global ecosystem works. There are many different approaches for estimating the net production of organic matter in the euphotic zone. We compare net biological oxygen production derived from a study of oxygen, nitrogen, and argon mass balance with nitrate uptake determined in N-15 incubation experiments in the mixed layer of the subarctic Pacific Ocean. Net community production rates determined by these two methods are within a factor of two with the incubations being, in one case, greater. This indicates that chemical mass balance and in vitro incubation measurements give similar results under circumstances where averaging over different time scales does not bias the comparison.