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| Titel |
Effect of peat quality on microbial greenhouse gas formation in an acidic fen |
| VerfasserIn |
M. Reiche, G. Gleixner, K. Küsel |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 1 ; Nr. 7, no. 1 (2010-01-13), S.187-198 |
| Datensatznummer |
250004373
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| Publikation (Nr.) |
 copernicus.org/bg-7-187-2010.pdf |
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| Zusammenfassung |
| Peatlands play an important role in the global carbon cycle and represent
both an important stock of soil carbon and a substantial natural source of
relevant greenhouse gases like CO2 and CH4. While it is known that
the quality of organic matter affects microbial degradation and
mineralization processes in peatlands, the manner in which the quality of
peat organic matter affects the formation of CO2 and CH4 remains
unclear. In this study we developed a fast and simple peat quality index in
order to estimate its potential greenhouse gas formation by linking the
thermo-degradability of peat with potential anaerobic CO2 and CH4
formation rates. Peat samples were obtained at several depths (0–40 cm) at
four sampling locations from an acidic fen (pH 4.7). CO2 and
CH4 formation rates were highly spatially variable and depended on
depth, sampling location, and the composition of pyrolysable organic matter.
Peat samples active in CO2 and CH4 formation had a quality index
above 1.35, and the fraction of thermally labile pyrolyzable organic matter
(comparable to easily available carbon substrates for microbial activity)
obtained by thermogravimetry was above 35%. Curie-point pyrolysis-gas
chromatography/mass spectrometry mainly identified carbohydrates and lignin
as pyrolysis products in these samples, indicating that undecomposed organic
matter was found in this fraction. In contrast, lipids and unspecific
pyrolysis products, which indicate recalcitrant and highly decomposed
organic matter, correlated significantly with lower CO2 formation and
reduced methanogenesis. Our results suggest that undecomposed organic matter
is a prerequisite for CH4 and CO2 development in acidic fens.
Furthermore, the new peat quality index should aide the estimation of
potential greenhouse gas formation resulting from peatland restoration and
permafrost thawing and help yield more robust models of trace gas fluxes
from peatlands for climate change research. |
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