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Iron fertilization of the austral ocean—The Hamburg Model Assessment
Author(s) -
Kurz Katharina D.,
MaierReimer Ernst
Publication year - 1993
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/92gb02910
Subject(s) - iron fertilization , biological pump , flux (metallurgy) , ocean general circulation model , carbon cycle , geochemical cycle , atmosphere (unit) , atmospheric sciences , environmental science , human fertilization , oceanography , climatology , chemistry , geology , general circulation model , nutrient , phytoplankton , environmental chemistry , meteorology , biology , physics , climate change , ecology , agronomy , organic chemistry , ecosystem
We have investigated the effect of an enhanced biological productivity, caused by an artificial iron fertilization, in the southern ocean with a three‐dimensional carbon cycle model, which is based on an ocean circulation obtained by an ocean general circulation model. The increase of the biological production did not result in a substantial increase of CO 2 uptake by the ocean, as it has been proposed by Martin et al. (1990). We have found that—assuming that the basic structure of the particulate downward flux does not change when higher production occurs—the ocean circulation provides a higher return flux of remineralized products that compensates two thirds of the effect of the higher export production on the atmospheric pCO 2 . This finding is only slightly modified when assuming a much deeper penetration of particle flux due to the fertilization. Owing to the nonlinearity of the buffer factor the absolute value of CO 2 reduction in the atmosphere is higher at high levels of pCO 2 . In view of the logarithmic dependency of the radiative forcing on CO 2 , the fertilization is more efficient at low CO 2 levels. With our carbon cycle model we have, in essence, confirmed earlier three‐dimensional model studies with a simplified geochemical cycling of the Princeton group (Sarmiento and Orr, 1991).