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| Titel |
Peatland CO2 emissions: Using 13C to quantify responses to land use change |
| VerfasserIn |
Helen Snell, David Robinson, Andrew J. Midwood |
| 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 |
250072895
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| Zusammenfassung |
| Soil is the largest terrestrial carbon reservoir and annually soils emit about 98 billion tonnes
of CO2which is derived from plant root and rhizosphere respiration (autotrophically fuelled
by photosynthesis) and microbial degradation of soil organic carbon (heterotrophic
respiration). These two processes are intrinsically linked by complex physical and
biochemical interactions.
In order to meet its GHG reductions targets the Scottish Government plans to
increase woodland cover from 17 to 25% by the second half of this century which
will inevitably lead to significant tree planting on peatland soils. Tree roots and
associated mycorrhiza will alter physical and biological conditions in the soil which
may affect the heterotrophic contribution to CO2 emissions and consequently the
long term landscape-scale carbon balance since the difference between net primary
productivity and heterotrophic respiration defines the terrestrial CO2 sink. Significant
uncertainties surround the response of peatlands to tree planting and predicted climate
changes.
At a field site in eastern Scotland we used natural abundance stable isotopes of carbon to
partition soil CO2 efflux into its heterotrophic and autotrophic components to determine
whether young Scots pine plantations affect heterotrophic respiration rates in peatland
soil. Rate and isotopic composition of soil CO2 efflux was measured in plantation
areas and in unforested heather moorland; soil and roots were then excavated and
separately incubated to establish the isotopic end members of a simple linear mixing
model.
Isotopic composition of soil efflux varies temporally and spatially across the site; young
Scots pine trees do not increase the heterotrophic flux from soil and therefore do not lead to a
net loss of soil carbon from these landscapes. |
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