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| Titel |
Soil organic matter transformation in cryoturbated horizons of permafrost affected soils |
| VerfasserIn |
Petr Čapek, Kateřina Diáková, Jan-Erik Dickopp, Jiří Bárta, Hana Šantrůčková, Birgit Wild, Joerg Schnecker, Georg Guggenberg, Norman Gentsch, Gustaf Hugelius, Peter Kuhry, Nikolaj Lashchinsky, Antje Gittel, Christa Schleper, Robert Mikutta, Juri Palmtag, Olga Shibistova, Tim Urich, Sergey Zimov, Andreas Richter |
| 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 |
250097828
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| Publikation (Nr.) |
 EGU/EGU2014-13445.pdf |
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| Zusammenfassung |
| Cryoturbated soil horizons are special feature of permafrost affected soils. These soils are
known to store great amount of organic carbon and cryoturbation undoubtedly contribute to it
to large extent. Despite this fact there is almost no information about soil organic matter
(SOM) transformation in cryoturbated horizons. Therefore we carried out long term
incubation experiment in which we inspect SOM transformation in cryoturbated as well as in
organic and mineral soil horizons under different temperature and redox regimes as potential
drivers. We found out that lower SOM transformation in cryoturbated horizons compared to
organic horizons was mainly limited by the amount of microbial biomass, which is extremely
low in absolute numbers or expressed to SOM concentration. The biochemical transformation
ensured by extracellular enzymes is relatively high leading to high concentrations of
dissolved organic carbon in cryoturbated horizons. Nevertheless the final step of SOM
transformation leading to C mineralization to CO2 or CH4 seems to be restricted by low
microbial biomass. Critical step of biochemical transformation of complex SOM is
dominated by phenoloxidases, which break down complex organic compounds to simple
ones. Their oxygen consumption greatly overwhelms oxygen consumption of the whole
microbial community. However the phenoloxidase activity shows strong temperature
response with optimum at 13.7°C. Therefore we suggest that apparent SOM stability in
cryoturbated horizons, which is expressed in old C14 dated age, is caused by low amount of
microbial biomass and restricted diffusion of oxygen to extracellular enzymes in field. |
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