Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia

Abstract

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 δ 13C and δ 15N 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 (R 2>0.55, p < 0.01) with FTIR-derived humification indices. The degree of decomposition was lowest at a site presently dominated by Sphagnum