Atmospheric Iron Deposition: Global Distribution, Variability, and Human Perturbations


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Mahowald N. M., Engelstaedter S., Luo C., Sealy A., Artaxo P., Benitez-Nelson C., ...More

ANNUAL REVIEW OF MARINE SCIENCE, vol.1, pp.245-278, 2009 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Review
  • Volume: 1
  • Publication Date: 2009
  • Doi Number: 10.1146/annurev.marine.010908.163727
  • Journal Name: ANNUAL REVIEW OF MARINE SCIENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.245-278
  • Keywords: aerosol deposition, climate change, deserts, AEROSOL OPTICAL DEPTH, LONG-RANGE TRANSPORT, TIME-SERIES STATION, SUPPLY-AND-DEMAND, ICE CORE RECORDS, MINERAL DUST, SAHARAN DUST, DESERT DUST, CLIMATE-CHANGE, AFRICAN DUST
  • Middle East Technical University Affiliated: Yes

Abstract

Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric iron cycle, and combustion sources of iron are responsible for the remaining 5%. Humans may be significantly perturbing desert dust (up to 50%). The sources of bioavailable iron ire less well understood than those of iron, partly because we do not know what speciation of the iron is bioavailable. Bioavailable iron can derive from atmospheric processing of relatively insoluble desert dust iron or from direct emissions of soluble iron from combustion sources. These results imply that humans could be substantially impacting it-on and bioavailable iron deposition to ocean regions, but there are large uncertainties in our understanding.