The impact of high levels of nitrogen deposition from the atmosphere (primarily from the
combustion of fossil fuels and transportation) on soil carbon fluxes and carbon
sequestration pathways in peatlands are uncertain and limit our understanding of its
consequence on peatlands’ role as global carbon sinks. An alteration in peatlands’ natural
carbon accumulation process could result in the increased release of CO2 into the
atmosphere, potentially increasing the greenhouse effect and contributing to climate
change.
Recent studies in forest soils have shown that high concentrations of inorganic nitrogen
accelerate the activity of key soil enzymes involved in the degradation of easily
decomposable litter (low lignin content) but slow down the decomposition of lignin
abundant litter. Peatland soils are adapted to slow rates of nitrogen mineralization;
therefore increasing the nitrogen supply in these environments may have an even deeper
impact on litter quality, potential litter decomposability, and overall carbon storage
capacity.
The aim of this study is to use plant wax biomarkers as proxies of vegetational change in
litter profiles. An alkane and alcohol profile database of peatland vegetation is currently
being characterized for comparison with samples taken from the Whim Moss
experimental site (Edinburgh) where different levels of nitrogen has been added to
peatland soil since 2002. A temporal study combining the MicroResp technique
(community level physiological profiles) and enzyme activity assays is considered to look
at the effect of litter compositional changes on soil microbial diversity and biological
activity. To better understand how nitrogen deposition in peatland soil affects the
mechanisms controlling carbon storage, the incorporation of stable isotope labelling (13C)
would allow direct determination of the fate of carbon into the different carbon pools and
better pin-point the changes in litter composition
