The atmospheric carbon dioxide response to oceanic primary productivity fluctuations

Data on the rate of primary production, the rate of sinking and oxidation of organic detritus, the rate of regeneration of calcium carbonate, the average rate of vertical mixing, and the vertical profile of dissolved carbon are consistent with a model of the ocean in which the downward transport of carbon by the sinking and oxidation of organic particulate matter is balanced by upward hydrodynamic mixing of dissolved inorganic carbon. A time dependent version of this model is used to make rough estimates of the effect of periodic and impulsive changes in the rate of primary production on the atmospheric CO₂ concentration. The computations suggest that a 1% decrease in marine biospheric productivity could result in a steady state increase of the atmospheric CO₂ concentration of from 0.5 to 2.5% depending on the rate of vertical mixing. Large but short term fluctuations in productivity, such as a die-off of the marine biosphere followed by an exponential recovery period, are estimated to produce smaller perturbations.Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.