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Mineralogy as a critical factor of dust iron solubility
Author(s) -
Journet Emilie,
Desboeufs Karine V.,
Caquineau Sandrine,
Colin JeanLouis
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl031589
Subject(s) - solubility , dissolution , mineral dust , feldspar , mineralogy , mineral , aerosol , iron fertilization , environmental chemistry , geology , biogeochemical cycle , chemistry , materials science , metallurgy , quartz , paleontology , organic chemistry , phytoplankton , nutrient
To understand the impact of dust deposition on ocean primary productivity, the evaluation of dust input is not sufficient, and the soluble iron supply is also needed. Measurements of iron in aerosols suggest a much higher solubility than in soil, implying substantial atmospheric processing of chemical or physical nature. Here, we have investigated the effect of the mineralogy on iron solubility. We have measured iron solubility from some minerals commonly found in dust (clay, feldspar and iron (hydr‐)oxides). Firstly, we observe a greater solubility of iron resulting from clays (~4%) in comparison to iron (hydr‐)oxides (<1%), independently of specific surface of minerals. Secondly, by considering amount of dissolved iron and the mineralogical composition of dust, our results indicate that dissolved iron fraction mainly comes from clay dissolution in contrast to that assumed in some biogeochemical models. In consequence, it appears that iron solubility is closely linked to the mineralogical composition of aerosol.