Effects of soil organic matter properties and microbial community composition on enzyme activities in cryoturbated arctic soils
Creators: name: Schnecker, Jörg
name: Wild, Birgit
name: Hofhansl, Florian
name: Alves, Ricardo J. Eloy
name: Barta, Jin
name: Čapek, Petr
name: Fuchslueger, Lucia
name: Gentsch, Norman
name: Gittel, Antje
name: Guggenberger, Georg
name: Hofer, Angelika
name: Kienzl, Sandra
name: Knoltsch, Anna
name: Lashchinskiy, Nikolay
name: Mikutta, Robert
name: Šantrůčková, Hana
name: Shibistova, Olga
name: Takriti, Mounir
name: Urich, Tim
name: Weltin, Georg
name: Richter, Andreas
Publisher: name: San Francisco : Public Library of Science
Year: 2014
Subjects: subject: cellulose 1,4 beta cellobiosidase
subject: cytosol aminopeptidase
subject: fatty acid
subject: monophenol monooxygenase
subject: nitrogen
subject: soil organic matter
subject: enzyme
subject: soil
subject: Arctic
subject: carbon mineralization
subject: controlled study
subject: decomposition
subject: enzyme activity
subject: geographic distribution
subject: microbial activity
subject: microbial community
subject: nitrogen mineralization
subject: nonhuman
subject: pH
subject: soil analysis
subject: soil depth
subject: soil property
subject: species composition
subject: structural equation modeling
subject: water content
subject: chemistry
subject: enzyme activation
subject: geography
subject: hydrolysis
subject: metabolism
subject: microbiology
subject: microflora
subject: Russian Federation
subject: Carbon
subject: Enzyme Activation
subject: Enzymes
subject: Geography
subject: Hydrolysis
subject: Microbiota
subject: Nitrogen
subject: Siberia
subject: Soil Microbiology
subject: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften

description: Enzyme-mediated decomposition of soil organic matter (SOM) is controlled, amongst other factors, by organic matter properties and by the microbial decomposer community present. Since microbial community composition and SOM properties are often interrelated and both change with soil depth, the drivers of enzymatic decomposition are hard to dissect. We investigated soils from three regions in the Siberian Arctic, where carbon rich topsoil material has been incorporated into the subsoil (cryoturbation). We took advantage of this subduction to test if SOM properties shape microbial community composition, and to identify controls of both on enzyme activities. We found that microbial community composition (estimated by phospholipid fatty acid analysis), was similar in cryoturbated material and in surrounding subsoil, although carbon and nitrogen contents were similar in cryoturbated material and topsoils. This suggests that the microbial community in cryoturbated material was not well adapted to SOM properties. We also measured three potential enzyme activities (cellobiohydrolase, leucine-amino-peptidase and phenoloxidase) and used structural equation models (SEMs) to identify direct and indirect drivers of the three enzyme activities. The models included microbial community composition, carbon and nitrogen contents, clay content, water content, and pH. Models for regular horizons, excluding cryoturbated material, showed that all enzyme activities were mainly controlled by carbon or nitrogen. Microbial community composition had no effect. In contrast, models for cryoturbated material showed that enzyme activities were also related to microbial community composition. The additional control of microbial community composition could have restrained enzyme activities and furthermore decomposition in general. The functional decoupling of SOM properties and microbial community composition might thus be one of the reasons for low decomposition rates and the persistence of 400 Gt carbon stored in cryoturbated material.