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| Titel |
Mg isotope fractionation during microbe-mineral interactions |
| VerfasserIn |
Insu Kim, Jong-Sik Ryu, Kwang-Sik Lee, Dongho Lee |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094407
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| Publikation (Nr.) |
 EGU/EGU2014-9815.pdf |
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| Zusammenfassung |
| Magnesium is involved in various biogeochemical processes important to the global climate
change over geological time-scale. Mg isotopes allow us to directly trace the Mg cycle in the
Earth’s surface but the factors controlling Mg isotopic compositions have not fully
understood yet. Here, we conducted a batch experiment using two bacterial species
(Shewanella putrefaciens and Burkholderia fungorum) and three major Mg-bearing minerals
(biotite, dolomite and hornblende). All elemental concentrations increased by 336 h and then
reached to steady-state values, of which Mg concentrations varied depending on minerals and
bacterial species. This result indicates that the mineral dissolution is affect by the presence of
microbes, which either provide organic acids or attach onto mineral surface. The
Mg isotopic compositions of initial minerals biotite, dolomite and hornblende are
-0.35oof biotite, -0.99oof dolomite, and -0.24oof hornblende, in δ26Mg. Similarly,
δ26Mg values increased by 336 h and reached to steady-state values, which also
varied with minerals and microbes. During dissolution of three minerals, the light
isotope of Mg is preferentially incorporated into the dissolved phases and then the
dissolved δ26Mg values become consistent with those of minerals with the time. |
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