title: Atmospheric iron deposition: global distribution, variability, and human perturbations.
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 are 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 iron and bioavailable iron deposition to ocean regions, but there are large uncertainties in our understanding.
authors.affiliation: Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14853, USA. mahowald@cornell.edu
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Mahowald
authors.forename: Sebastian
authors.initials: S
authors.lastname: Engelstaedter
authors.forename: Chao
authors.initials: C
authors.lastname: Luo
authors.forename: Andrea
authors.initials: A
authors.lastname: Sealy
authors.forename: Paulo
authors.initials: P
authors.lastname: Artaxo
authors.forename: Claudia
authors.initials: C
authors.lastname: Benitez-Nelson
authors.forename: Sophie
authors.initials: S
authors.lastname: Bonnet
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Patrick Y
authors.initials: PY
authors.lastname: Chuang
authors.forename: David D
authors.initials: DD
authors.lastname: Cohen
authors.forename: Francois
authors.initials: F
authors.lastname: Dulac
authors.forename: Barak
authors.initials: B
authors.lastname: Herut
authors.forename: Anne M
authors.initials: AM
authors.lastname: Johansen
authors.forename: Nilgun
authors.initials: N
authors.lastname: Kubilay
authors.forename: Remi
authors.initials: R
authors.lastname: Losno
authors.forename: Willy
authors.initials: W
authors.lastname: Maenhaut
authors.forename: Adina
authors.initials: A
authors.lastname: Paytan
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Prospero
authors.forename: Lindsey M
authors.initials: LM
authors.lastname: Shank
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Siefert
mesh_terms: D000336:Aerosols / Q000737:chemistry; D000818:Animals; D001272:Atmosphere / Q000737:chemistry*; D004391:Dust / Q000032:analysis; D006801:Humans; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D009792:Oceans and Seas; D012623:Seawater / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000336:Aerosols; D004391:Dust; D007501:Iron