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Improved theory of ocean iron cycle resolves modelling issues
A revised conceptual model of the chemical and physical forms of iron in the ocean reconciles the mismatch between observations and simulations of the amount of dissolved iron in seawater — and might aid climate predictions.
Marine microorganisms known as phytoplankton use carbon dioxide to build their bodies, and the energy of sunlight to fuel their metabolisms. When they die, they sink to the ocean floor, carrying carbon with them. These organisms therefore act as the primary link between CO2 in the atmosphere and carbon sequestered in ocean sediments. However, the scarcity of iron — a nutrient required for life — in seawater limits the growth of phytoplankton1, and therefore the quantity of carbon that can be sequestered. The amount and chemical forms of iron available to phytoplankton are key to how the ocean and atmosphere interact. Writing in Nature, Tagliabue et al.2 report a modelling framework and numerical tool that address some of the intricacies of marine iron chemistry and solve long-standing inconsistencies in simulations of the iron cycle.