 |
| Titel |
Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia |
| VerfasserIn |
T. Broder, C. Blodau, H. Biester, K. H. Knorr |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 4 ; Nr. 9, no. 4 (2012-04-20), S.1479-1491 |
| Datensatznummer |
250006955
|
| Publikation (Nr.) |
 copernicus.org/bg-9-1479-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| Ombrotrophic bogs in southern Patagonia have been examined with regard to
paleoclimatic and geochemical research questions but knowledge about organic
matter decomposition in these bogs is limited. Therefore, we examined peat
humification with depth by Fourier Transformed Infrared (FTIR) measurements
of solid peat, C/N ratio, and δ13C and δ15N
isotope measurements in three bog sites. Peat decomposition generally
increased with depth but distinct small scale variation occurred, reflecting
fluctuations in factors controlling decomposition. C/N ratios varied mostly
between 40 and 120 and were significantly correlated (R2 > 0.55, p
< 0.01) with FTIR-derived humification indices. The degree of
decomposition was lowest at a site presently dominated by Sphagnum mosses. The peat
was most strongly decomposed at the driest site, where currently
peat-forming vegetation produced less refractory organic material, possibly
due to fertilizing effects of high sea spray deposition. Decomposition of
peat was also advanced near ash layers, suggesting a stimulation of
decomposition by ash deposition. Values of δ13C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while δ15N in the peat varied around zero and did not consistently relate to
any decomposition index. Concentrations of DOM partly related to C/N ratios,
partly to FTIR derived indices. They were not conclusively linked to the
decomposition degree of the peat. DOM was enriched in 13C and in
15N relative to the solid phase probably due to multiple microbial
modifications and recycling of N in these N-poor environments. In summary,
the depth profiles of C/N ratios, δ13C values, and FTIR spectra
seemed to reflect changes in environmental conditions affecting
decomposition, such as bog wetness, but were dominated by site specific
factors, and are further influenced by ash deposition and possibly by sea
spray input. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|