Priming effect increases with depth in a boreal forest soil

Published Date
August 2016, Vol.99:104–107, doi:10.1016/j.soilbio.2016.05.001

Short communication

Title 

Priming effect increases with depth in a boreal forest soil

• Author 

• Kristiina Karhu ^a,,
• Emmi Hilasvuori ^b
• Hannu Fritze ^c
• Christina Biasi ^d
• Hannu Nykänen ^e
• Jari Liski ^b
• Pekka Vanhala ^b
• Jussi Heinonsalo ^f
• Jukka Pumpanen ^d

• aDepartment of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland
• bFinnish Environment Institute, P.O. Box 140, FI-00251 Helsinki, Finland
• cNatural Resources Institute Finland, P.O. Box 18, FI-01301 Vantaa, Finland
• dDepartment of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland
• eDepartment of Biological and Environmental Science, University of Jyvaskyla, P.O. Box 35, FI-40014, Finland
• fDepartment of Food and Environmental Sciences, University of Helsinki, P.O. Box 56, FI-00014, Finland

Received 9 April 2015. Revised 20 April 2016. Accepted 1 May 2016. Available online 11 May 2016.

Highlights

• •
  We studied priming effects (PE) in different layers of a boreal forest soil.
• •
  ¹³C labeled glucose was added at different amounts relative to microbial biomass.
• •
  PE increased with depth, and thus with decreasing C and N availability.
• •
  The relationship between PE and the added glucose amount depended on the soil layer.
• •
  If C inputs into subsoil increase, SOM decomposition could be enhanced through PEs.

Abstract

Climate warming increases labile carbon (C) inputs to soil through increased photosynthesis and C allocation belowground. This could counterintuitively lead to losses of soil C via priming effects (PE): the stimulation of soil organic matter (SOM) decomposition caused by labile C addition. Systematic quantification of PEs in different ecosystems is needed. We measured PEs of free-living soil microbes in different layers of a boreal forest soil, and found that the relative magnitude of the PE increased with soil depth. The relationship between relative PE and the added glucose amount also depended on the soil layer. Our results indicate that the decomposition of SOM in deeper soil layers could be significantly increased due to PE, if labile C inputs into these layers increase.

Keywords

• Priming effect
• Boreal forest soil
• Climate change
• C & N interactions

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 Table 1

Table 1.

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• ∗ 
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