Comparing Shifts in Abundance of Molecular Biomarkers with Depth from Natural and Drained Sites in a Finnish Mire Using Py-GC/MS
Abstract
Peatlands serve as an important terrestrial carbon (C) store. Currently, impacts from anthropogenic climate change, as well as drainage for forestry, agriculture, and extraction have impacted peatlands globally, causing an increase in aerobic decomposition and shifting the C balance in degraded sites from sink to source. For C storage to be effective in peatland ecosystems, C output produced from decomposition processes must not exceed the C input from vegetation. However, changes and shifts in this balance cannot always be observed macroscopically. By characterizing molecular markers within the peat profile, periods of oxic and anoxic conditions can be delineated using ratios of microbial matter (particularly those responsible for aerobic decomposition) to undecomposed plant material, even in profiles where changes in conditions are not directly visible.
To determine differences in biomarker concentrations between natural and degraded peatland sites, peat cores were collected from natural and drainage-affected locations from an ombrotrophic mire in Lakkasuo, Finland, and analyzed via pyrolysis-gas chromatography mass spectrometry (Py-GC/MS). Biomarkers (acetic acid, toluene, Sphagnum phenols, Levoglucosan, etc.) indicating changes in vegetation composition as well as markers for aerobic and anaerobic decomposition were quantified for and used to interpret changes with depth in profiles from each of the two sites. Interpretation of the pyrograms revealed differences between the drained and natural sites, indicating that peat molecular composition reflects the state of a peatland. As part of a larger study, these shifts in molecular composition are related to shifts in 13C and 15N isotopic signal abundance and macroscopic analysis from the same cores, in order to evaluate the use of different biogeochemical analysis techniques as proxies to assess peatland restoration.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B43M2999W
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0476 Plant ecology;
- BIOGEOSCIENCESDE: 0486 Soils/pedology;
- BIOGEOSCIENCESDE: 1630 Impacts of global change;
- GLOBAL CHANGE