Project Details
Abstract
Priming effects of moss leachates on soil organic matter dynamics
• Wider research context: The poikilohydric life style of bryophytes implies that active phases in moist state
may alternate with inactive phases in desiccated state, which requires a range of physiological adaptations,
like the accumulation of sugars, polyols and antioxidants. Despite such adaptations, re-wetting of
desiccated mosses causes considerable leakage of intracellular metabolites due to membrane restructuring
and damage of cell membranes. The ecosystem implication of these drying-rewetting cycles of mosses is
that major rain events following intermittent periods of dry weather cause a pulse of labile carbon-rich
substrates leached from the moss layer, which is subsequently washed into the soil. The impact of this Cflush on soil microbial activity is, however, yet unknown.
• Research questions: In this project we address two main research questions:
(1) Does the pulse of low molecular weight organic compounds in moss leachates stimulate soil microbial
activity and enhance microbial decomposition processes of soil organic matter (SOM), i.e. cause a positive
priming effect? (2) Does the effect of moss leachates on soil microbial activity differ between moss species
and are such differences linked to the concentration of leached DOC or to the chemical quality of the
compounds contained in moss leachates?
• Approach: We will investigate these research questions by a mesocosm experiment using two soil types
to which leachates of four moss species will be added, and we will subsequently determine effects on soil
microbial processes (respiration, extracellular enzyme activities and microbial N transformations) and
microbial community composition, and also analyse the chemical composition of the moss leachates. We
will use leachates of 13C-labelled mosses, which will allow us to trace the fate of moss leachates in soil and
to elucidate priming effects on SOM decomposition. The mesocosm experiment will be complemented by
in-situ moss leachate collections in two spruce forests over one growing season, and by a pre-experiment
investigating the relationship between moss leaching and desiccation intensity.
• Level of originality: In this study we will perform the first comprehensive analysis of the effects of organic
compounds leached from mosses on soil microbial communities, microbial decomposition processes of
SOM and microbial necromass formation. By interlinking plant physiological, soil microbiological and
biogeochemical aspects, the proposed study will improve our understanding of the role of bryophytes in the
functioning of montane forest ecosystems and thus help to refine models of C and nutrient cycling in mossrich ecosystems under climate change.
• Primary researchers involved:
Marianne Koranda (PI, University of Vienna, Austria)
Wolfgang Wanek (Univ. of Vienna)
Harald G. Zechmeister (Univ. of Vienna)
• Wider research context: The poikilohydric life style of bryophytes implies that active phases in moist state
may alternate with inactive phases in desiccated state, which requires a range of physiological adaptations,
like the accumulation of sugars, polyols and antioxidants. Despite such adaptations, re-wetting of
desiccated mosses causes considerable leakage of intracellular metabolites due to membrane restructuring
and damage of cell membranes. The ecosystem implication of these drying-rewetting cycles of mosses is
that major rain events following intermittent periods of dry weather cause a pulse of labile carbon-rich
substrates leached from the moss layer, which is subsequently washed into the soil. The impact of this Cflush on soil microbial activity is, however, yet unknown.
• Research questions: In this project we address two main research questions:
(1) Does the pulse of low molecular weight organic compounds in moss leachates stimulate soil microbial
activity and enhance microbial decomposition processes of soil organic matter (SOM), i.e. cause a positive
priming effect? (2) Does the effect of moss leachates on soil microbial activity differ between moss species
and are such differences linked to the concentration of leached DOC or to the chemical quality of the
compounds contained in moss leachates?
• Approach: We will investigate these research questions by a mesocosm experiment using two soil types
to which leachates of four moss species will be added, and we will subsequently determine effects on soil
microbial processes (respiration, extracellular enzyme activities and microbial N transformations) and
microbial community composition, and also analyse the chemical composition of the moss leachates. We
will use leachates of 13C-labelled mosses, which will allow us to trace the fate of moss leachates in soil and
to elucidate priming effects on SOM decomposition. The mesocosm experiment will be complemented by
in-situ moss leachate collections in two spruce forests over one growing season, and by a pre-experiment
investigating the relationship between moss leaching and desiccation intensity.
• Level of originality: In this study we will perform the first comprehensive analysis of the effects of organic
compounds leached from mosses on soil microbial communities, microbial decomposition processes of
SOM and microbial necromass formation. By interlinking plant physiological, soil microbiological and
biogeochemical aspects, the proposed study will improve our understanding of the role of bryophytes in the
functioning of montane forest ecosystems and thus help to refine models of C and nutrient cycling in mossrich ecosystems under climate change.
• Primary researchers involved:
Marianne Koranda (PI, University of Vienna, Austria)
Wolfgang Wanek (Univ. of Vienna)
Harald G. Zechmeister (Univ. of Vienna)
Status | Active |
---|---|
Effective start/end date | 6/07/22 → 14/02/26 |
Keywords
- bryophytes
- moss leachates
- soil organic matter
- microbial decomposition processes
- soil microbial community
- carbon and nutrient cycling