30 - 300 g C/m^2/year
||Duursma EK, Boisson MPRM, Global oceanic and atmospheric oxygen stability considered in relation to the carbon-cycle and to different time scales. Oceanologica Acta (0399-1784) (Gauthier-Villars), 1994 , Vol. 17 , N. 2 , P. 117-141 link p.135 right column 3rd paragraph
||Berger W.H., V.S. Smetacek and G. Wefer (1989). Ocean Productivity and Paleoproductivity. An overview, in: Productivity of the Ocean Present and Past, W.H. Berger, V.S. Smetacek and G. Wefer, editors. John Wiley and Sons, New York, USA, 1-34
||P.135 right column 3rd paragraph: "The world oceans have, on the one hand, a relatively small oxygen content which is 1/120 (Tab. 2) of that of the atmospheric oxygen reserve. But on the other band, the oceans have a very large interface with the atmosphere, amounting to 70 % of the earth's surface and a primary
productivity which ranges from 30 to 300 g C/m^2/yr (primary source)."