REDOX STABILIZATION OF THE ATMOSPHERE AND OCEANS BY PHOSPHORUS-LIMITED MARINE PRODUCTIVITY

Data from modern and ancient marine sediments demonstrate that burial of the limiting nutrient phosphorus is less efficient when bottom wate rs are low in oxygen. Mass-balance calculations using a coupled model of the biogeochemical cycles of carbon, phosphorus, oxygen, and iran i ndicate that the redox dependence of phosphorus burial in the oceans p rovides a powerful forcing mechanism for balancing production and cons umption of atmospheric oxygen over geologic time. The oxygen-phosphoru s coupling further guards against runaway ocean anoxia. Phosphorus-med iated redox stabilization of the atmosphere and oceans may have been c rucial to the radiation of higher life forms during the Phanerozoic.