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| Titel |
Peatland carbon cycling at a Scottish wind farm: the role of plant-soil interactions |
| VerfasserIn |
Harriett Richardson, Jeanette Whitaker, Susan Waldron, Nick Ostle |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072208
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| Zusammenfassung |
| Peatlands play a fundamental role in the terrestrial carbon cycle by storing 1/3 of the world’s
soil carbon (Limpens et al. 2008). In the UK, peatlands are often located in areas with
potential for electricity generation by harvesting wind energy. Concerns have been raised,
however, over the stability of these carbon stocks when large scale wind developments are
sited upon them.
This project aims to improve understanding of the impact of wind farms on carbon
sequestration in peatlands. Wind turbine ‘wake-effects’ can alter microclimatic conditions, as
a result of significant differences in air temperature, humidity, wind speed and turbulence
(Baidya Roy and Traiteur 2010). These changes are likely to have a significant impact on
above and below ground abiotic conditions and biotic properties, together with the processes
they regulate that govern peatland carbon cycling. Specifically, the effects of interactions
between typical peatland plant functional types (graminoids, bryophytes and shrubs) (Ward
et al. 2009) and peat microbial community composition and function are poorly
resolved.
We examined a spatial gradient across an area of blanket bog at Black Law wind farm
(Lanarkshire, Scotland) and executed a series of controlled mesocosm experiments to
examine the impacts of potential microclimatic changes on plant-soil interactions and carbon
sequestration processes. In particular we focused on the form and function of plant and
microbial communities as determinants of decomposition (Ward et al. 2010) and greenhouse
gas (GHG) emissions (Artz 2009).
Measurements of plant-litter-soil carbon, nitrogen, microbial community composition
(i.e. phospholipid fatty acid biomarkers) and litter mass loss have been made across the wind
farm peatland to attribute spatial variance in biotic and biogeochemical properties. In
addition, multi-factorial mesocosm experiments have been made to determine how abiotic
and biotic changes caused by wind farm effects could influence peat GHG emissions. These
experiments used intact peat cores to assess the interacting effects of temperature, water
table and plant functional type on GHG fluxes and rates of peatland plant litter
decomposition.
Results show significant differences in soil chemistry and microbial community
composition across the wind farm gradient with few seasonal effects. Findings from
controlled mesocosm experiments offer evidence that CO2 and CH4 fluxes were significantly
altered over a 4Ë C temperature range at three different water table heights. The more
anaerobic cores produced greatest CH4 fluxes, whereas warmer more aerobic conditions
favoured CO2 production. Plant functional types differentially influence emissions, with
graminoid cores exerting the greatest control over GHG fluxes. Significant synergistic
effects suggest that abiotic drivers are key, yet plant-soil biology interacts to mediate
carbon cycling. Thus, changes to plant-soil interactions resulting from wind farm
‘wake-effects’ could have important implications for peatland carbon sequestration. |
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