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| Titel |
The effect of a reciprocal peat transplant between two contrasting Central European sites on C cycling and C isotope ratios |
| VerfasserIn |
M. Novak, L. Zemanova, F. Buzek, I. Jackova, M. Adamova, A. Komarek, M. A. Vile, R. Kelman Wieder, M. Stepanova |
| 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. 3 ; Nr. 7, no. 3 (2010-03-08), S.921-932 |
| Datensatznummer |
250004585
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| Publikation (Nr.) |
 copernicus.org/bg-7-921-2010.pdf |
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| Zusammenfassung |
| An 18-month reciprocal peat transplant experiment was conducted between two
peatlands in the Czech Republic. Both sites were 100%
Sphagnum-covered, with no vascular plants, and no hummocks and hollows. Atmospheric
depositions of sulfur were up to 10 times higher at the northern site Velke
jerabi jezero (VJJ), compared to the southern site Cervene blato (CB).
Forty-cm deep peat cores, 10-cm in diameter, were used as transplants and
controls in five replicates. Our objective was to evaluate whether CO2
and CH4 emissions from Sphagnum peat bogs are governed mainly by organic matter
quality in the substrate, or by environmental conditions. Emission rates and
δ13C values of CO2 and CH4 were measured in the
laboratory at time t=18 months. All measured parameters converged to those
of the host site, indicating that, at least in the short-term perspective,
environmental conditions were a more important control of greenhouse gas
emissions than organic carbon quality in the substrate. Since sulfate
reducers outcompete methanogens, we hypothesized that the S-polluted site
VJJ should have lower methane emissions than CB. In fact, the opposite was
true, with significantly (p<0.01) higher methane emissions from VJJ.
Additionally, as a first step in an effort to link C isotope composition of
emitted gases and residual peat substrate, we determined whether multiple
vertical δ13C profiles in peat agree. A high degree of
within-site homogeneity in δ13C was found. When a specific
vertical δ13C trend was seen in one peat core, the same trend
was also seen in all the remaining peat cores from the wetland. The δ13C
value increased downcore at both CB and VJJ. At VJJ, however, 20
cm below surface, a reversal to lower δ13C downcore was seen.
Based on 210Pb dating, peat at 20-cm depth at VJJ was only 15 years
old. Increasing δ13C values in VJJ peat accumulated between
1880–1990 could not be caused by assimilation of atmospheric CO2
gradually enriched in the light isotope 12C due to fossil fuel burning.
Rather they were a result of a combination of isotope fractionations
accompanying assimilation and mineralization of Sphagnum C. These isotope
fractionations may record information about past changes in C storage in
wetlands. |
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