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Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 11, issue 23
Biogeosciences, 11, 7051–7060, 2014
https://doi.org/10.5194/bg-11-7051-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Climate extremes and biogeochemical cycles in the terrestrial...

Biogeosciences, 11, 7051–7060, 2014
https://doi.org/10.5194/bg-11-7051-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 12 Dec 2014

Research article | 12 Dec 2014

Increased winter soil temperature variability enhances nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

J. Schuerings1,2, A. Jentsch1, V. Hammerl3, K. Lenz2, H. A. L. Henry4, A. V. Malyshev2, and J. Kreyling5 J. Schuerings et al.
  • 1Disturbance Ecology, BayCEER, University of Bayreuth, 95440 Bayreuth, Germany
  • 2Biogeography, BayCEER, University of Bayreuth, 95440 Bayreuth, Germany
  • 3Research Unit Environmental Genomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
  • 4Biology, University of Western Ontario, London, Ontario, Canada
  • 5Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Ernst-Moritz-Arndt University Greifswald, 17487 Greifswald, Germany

Abstract. Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to increased soil temperature variability, and potentially to changes in nutrient cycling. Here, we experimentally evaluated the effects of increased winter soil temperature variability on selected aspects of the N-cycle in mesocosms containing different plant community compositions. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and drier lowland site.

Increased soil temperature variability enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N) availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the potential activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the 15N signal in leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses.

Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling). While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant N uptake in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

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This article examines the effects of short winter warming pulses on temperate heathland and grassland mesocosms regarding nitrogen cycling, soil biotic activity and decomposition.
This article examines the effects of short winter warming pulses on temperate heathland and...
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