POSSIBLE EFFECTS OF IRON FERTILIZATION IN THE SOUTHERN OCEAN ON ATMOSPHERIC CO 2 CONCENTRATION

• Main Authors: Fortunat Joos, Ulrich Siegenthaler, Jorge L. Sarmiento
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Southern Ocean
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.358.1013; http://www.gfdl.noaa.gov/bibliography/related_files/fj9101.pdf?PHPSESSID=5b5ea82aa75249a7b4a1fb04ce2c4fe4

Abstract. Recently, it was proposed (Baum, 1990 and Martin et al., 1990a, 1990b) that the southern ocean should be fertilized with iron to stimulate biological productivity, thus enhancing the flux of organi carbon from surface to depth, thereby lowering the concentration of inorgani carbon in surface water and in turn the atmospheric CO2 concentration. We explore the possible impact of a hypothetical iron fertilization on atmospheric CO2 levels during the next century using a high-latitude exchange/interior diffusion advection model. Assuming as an upper-limit scenario that it is possible to stimulate the uptake of the abundant nutrients in the southern ocean, the maximum atmospheric CO2 depletion is 58 ppm after 50 years and 107 ppm after 100 years. This scenario requires completely effective Fe fertilization to be carded out over 16 % of the world ocean area. Sensitivity stud/es and comparison with other models suggest that the errors in these limits due to uncertainties in the transport parameters, which are determined by calibrating the model with radiocarbon and validated with CFC-11 measurements, range from-29 % to +17%. If ironstimulated biological productivity is halted during the six winter months, the additional oceanic CO2 uptake is reduced by 18%. Possible changes in surface water alkalinity alter the result of iron fertilization by less than +9 % to-28%. Burial of the iron-induced particle flux as opposed to remineralization in the deep ocean