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| Titel |
Dynamics of atmospheric-methane oxidation in glacier-forefield soils |
| VerfasserIn |
Eleonora Chiri, Philipp A. Nauer, Edda-Marie Rainer, Ruth Henneberger, Josef Zeyer, Martin H. Schroth |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102053
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| Publikation (Nr.) |
 EGU/EGU2015-1330.pdf |
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| Zusammenfassung |
| Mature upland soils are currently considered the sole terrestrial sink for atmospheric methane
(CH4). But little is known about CH4 dynamics in young,
developing soil ecosystems such as glacier forefields formed by progressive glacial retreat.
Glacier forefields are situated on diverse bedrock types, exhibit a continuum of soil age
(chronosequence), and are comprised of various geomorphological landforms, which may
differ in physicochemical properties. These features may affect activity and community
structure of aerobic methane-oxidizing bacteria (MOB) catalyzing atmospheric
CH4 oxidation. Moreover, MOB activity and community structure may be
affected by environmental parameters subject to seasonal variability such as soil temperature,
water content, and nutrient availability.
The aim of this study was to assess spatial and seasonal variability in atmospheric
CH4 oxidation in glacier-forefield soils derived from siliceous and calcareous
bedrock. Specifically, we quantified soil-atmosphere CH4 flux and
CH4 oxidation activity using the soil-gas-profile method and static flux
chambers in soils of different age and belonging to different landforms. In these soils MOB
abundance and variation in community structure were assessed by targeting the functional
gene pmoA using quantitative PCR, TRFLP-based cluster analysis, and high-throughput
DNA-sequencing technology. Seasonal variability in atmospheric CH4
oxidation was assessed based on the same attributes measured with high temporal resolution
throughout one snow-free season.
Most glacier-forefield soils acted as a sink for atmospheric CH4 regardless
of bedrock type, and CH4 flux (-0.082 to -2.2 mg CH4
m-2 d-1) and MOB abundance (2.4x103 to 5.5x105 pmoA
genecopies (g soil w.w.)-1) increased significantly with soil age. Cluster analysis revealed
variations in MOB community composition related to bedrock type rather than
soil age, suggesting that distinct MOB communities provided a similar ecosystem
service in soils on different bedrock. On the other hand, substantial differences in
CH4 flux were noted between soils of different landforms, with largest fluxes
observed in well-drained sandhills (see above) and considerably smaller fluxes
in fluvial landforms. Methane flux and oxidation activity revealed a prominent
seasonal variability, attenuated in older soils. Based on our findings we propose a
pattern for the establishment of the soil CH4 sink in glacier forefields. |
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