glacial-interglacial Co2 change : the iron hypothesis

摘要: Several explanations for the 200 to 280 ppm glacial/interglacial change in atmospheric CO2 concentrations deal with variations southern ocean phytoplankton productivity and related use or nonuse of major plant nutrients. An hypothesis is presented herein which arguments are made that new today's (7.4 × 1013g yr−1) limited by iron deficiency, hence unable take advantage excess surface nitrate/phosphate that, if used, could result total production 2−3 1015 g C yr−1. As a consequence Fe-limited productivity, Holocene interglacial levels (preindustrial) as high they were during last (≈ ppm). In contrast, dust Fe supplies 50 times higher glacial maximum (LGM). Because this enrichment, growth may have been greatly enhanced, larger amounts upwelled nutrients resulting stimulation contributed LGM drawdown less than ppm. Background information support presented.