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Chemically and Geographically Distinct Solid-Phase Iron Pools in the Southern Ocean
- von der Heyden, B. P., Roychoudhury, A. N., Mtshali, T. N., Tyliszczak, T., Myneni, S. C. B.
- Science 2012 v.338 no.6111 pp. 1199-1201
- X-radiation, aluminum, bioavailability, iron, microscopy, mineralogy, oceans, oxidation, phytoplankton, primary productivity, solubility, spectroscopy
- Swimming in Iron Pools Because iron is essential for marine phytoplankton growth, its availability limits the primary productivity of the oceans. Iron is typically bioavailable only when present in a dissolved state; however, a large fraction of the total iron in the oceans exists as tiny solid-phase particles ranging in size from a few nanometers to a few micrometers. von der Heyden et al. (p. 1199) used high-resolution x-ray microscopy and spectroscopy to characterize the distribution of iron particles along two transects of the Southern Ocean. Analysis of a number of individual particles reveals strong variation in iron oxidation state, particle mineralogy, and substitution of aluminum for iron—all of which control the solubility, and hence bioavailability, of iron.