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| Titel |
Stabilization of microbial residues by co-precipitation with Fe and Al
oxides |
| VerfasserIn |
Anja Miltner, Jan Achtenhagen, Matthias Kästner |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127812
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| Publikation (Nr.) |
 EGU/EGU2016-7727.pdf |
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| Zusammenfassung |
| Recent studies have shown that microbial residues contribute significantly to soil organic
matter (SOM) formation. This material, however, is readily degradable and thus needs to be
stabilized in soil. We hypothesize that the interaction with minerals, in particular
co-precipitation with metal oxyhydroxides, plays an important role in stabilization of cell
envelope material. We therefore analyzed the mineralization of 14C-labelled Escherichia coli
cells and cell envelope fragments during incubation of the cell materials alone or after
co-precipitation with either Fe or Al oxyhydroxide. We also tested the effect of
environmental conditions, in particular oxygen supply and redox potential, on the stabilizing
effect of the mineral phases. Co-precipitation with both Fe and Al oxyhydroxides
decreased the mineralization significantly, indicating strong protection of biomass and
biomass-derived fragments. Surprisingly, the mineralization of intact cells was higher
than that of cell envelope fragments. This points to a higher recalcitrance of the
cell envelope fragments, which therefore may be selectively enriched in SOM.
Reductive conditions obtained after water-logging combined with excessive supply of an
easily available carbon source resulted in increased mineralization in the treatments
containing Fe oxyhydroxides, due to reductive dissolution of the Fe oxyhydroxide and
thus loss of the stabilizing agent. We therefore conclude that co-precipitation with
and incrustation by Fe or Al oxyhydroxides is a relevant stabilization mechanism
for microbial residues. The same mechanism also may apply for SOM in general. |
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