Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 9, issue 11
Biogeosciences, 9, 4537–4551, 2012
https://doi.org/10.5194/bg-9-4537-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 9, 4537–4551, 2012
https://doi.org/10.5194/bg-9-4537-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 16 Nov 2012

Research article | 16 Nov 2012

Effects of stoichiometry and temperature perturbations on beech leaf litter decomposition, enzyme activities and protein expression

K. M. Keiblinger1,*, T. Schneider2,*, B. Roschitzki3, E. Schmid2, L. Eberl2, I. Hämmerle4, S. Leitner1,4, A. Richter4, W. Wanek4, K. Riedel2,5, and S. Zechmeister-Boltenstern1 K. M. Keiblinger et al.
  • 1BOKU – University of Natural Resources and Life Sciences, Institute of Soil Research, Department of Forest- and Soil Sciences, Peter-Jordan Strasse 82, 1190 Vienna, Austria
  • 2University of Zurich, Institute of Plant Biology, Winterthurerstrasse 190, 8057 Zürich, Switzerland
  • 3Functional Genomics Center, University and ETH Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
  • 4Department of Chemical Ecology and Ecosystem Research, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
  • 5Institute of Microbiology, University Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, 17487 Greifswald, Germany
  • *These authors contributed equally to this work.

Abstract. Microbes are major players in leaf litter decomposition and therefore advances in the understanding of their control on element cycling are of paramount importance. Our aim was to investigate the influence of leaf litter stoichiometry in terms of carbon (C) : nitrogen (N) : phosphorus (P) ratios on the decomposition processes and to track changes in microbial community structures and functions in response to temperature stress treatments. To elucidate how the stoichiometry of beech leaf litter (Fagus sylvatica L.) and stress treatments interactively affect the microbial decomposition processes, a terrestrial microcosm experiment was conducted. Beech litter from different Austrian sites covering C:N ratios from 39 to 61 and C:P ratios from 666 to 1729 were incubated at 15 °C and 60% moisture for six months. Part of the microcosms were then subjected to severe changes in temperature (+30 °C and −15 °C) to monitor the influence of temperature stress. Extracellular enzyme activities were assayed and respiratory activities measured. A semi-quantitative metaproteomics approach (1D-SDS PAGE combined with liquid chromatography and tandem mass spectrometry; unique spectral counting) was employed to investigate the impact of the applied stress treatments in dependency of litter stoichiometry on structure and function of the decomposing community. In litter with narrow C:nutrient (C:N, C:P) ratios, microbial decomposers were most abundant. Cellulase, chitinase, phosphatase and protease activity decreased after heat and freezing treatments. Decomposer communities and specific functions varied with site, i.e. stoichiometry. The applied stress combined with the respective time of sampling evoked changes of enzyme activities and litter pH. Freezing treatments resulted in a decline in residual plant litter material and increased fungal abundance, indicating slightly accelerated decomposition. Overall, a strong effect of litter stoichiometry on microbial community structures and functions was detected, but decomposition was mainly driven by a combination of the investigated factors. Temperature perturbations resulted in short- to medium-term alterations of microbial functions; especially high temperature treatments blocked decomposing enzymes.

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