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| Titel |
Rhizosphere activity and methane oxidation in a temperate forest soil |
| VerfasserIn |
Catherine S. Moody, Jens-Arne Subke, Naomi R. Voke, Robert D. Holden, Phil Ineson, Yit Arn Teh |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042597
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| Zusammenfassung |
| Methane (CH4) concentrations in the Earth’s atmosphere have increased dramatically over
recent decades. An abundance of studies indicate that the magnitude of natural methane
efflux from wetlands is likely to increase due to climate change. However, the role of
vegetation and soils in upland methane oxidation are less well understood. Well-aerated soils
are known to be sites of methane oxidation, and amongst a range of abiotic environmental
parameters, soil moisture has been identified as critical regulator of the methane
oxidation rates. However, the role of microbial activity within the soil, particularly C
turnover in the plant rhizosphere, has not been investigated as a means for regulating
methanotrophy.
We combined a continuous soil CO2 efflux system (Li-Cor Biosciences, LI-8100)
with a Cavity-Ringdown-Spectroscopy Fast Greenhouse Gas Analyser (Los Gatos
Research Inc.) to measure soil CH4 oxidation in a pine forest in NE England. The
soil has a shallow organic layer overlaying a well-draining sandy gley soil. Fluxes
were measured from three different collar treatments: (1) excluding both root and
ectomycorrhizal (EM) hyphae by trenching using deep collars, (2) excluding roots
but allowing access by EM hyphae, and (3) unmodified forest soil (i.e. including
both roots and EM hyphae). All collars were protected from natural throughfall,
and received weekly–averaged amounts of throughfall based on collections in the
stand.
Data from two months in early summer 2009 indicate that CH4 oxidation in collars with
an intact rhizosphere is more than twice that of either of the exclusion treatments (averaging
approx. 90 g ha-1 d-1 in that period). We observed higher fluxes when soils were dryer (i.e.
with increasing time since watering), indicating a significant influence of moisture. Despite
the confounding effects of soil moisture associated with root water uptake in the unmodified
soil collars, we argue that rhizosphere activity is an overlooked component in methanotrophy
in aerated soils. C supply from plants by both roots and EM hyphae appears to be linked
to the rate at which methanotrophs oxidise methane with potential feedbacks on
methane oxidation rates following altered plant productivity driven by climatic change. |
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