Eleanor Swain, PhD studentship, University of Newcastle (2008-2011)

Summary

This project was designed to study the fundamental processes controlling carbon cycling in soil within natural and managed ecosystems. This study aimed to provide a detailed and comprehensive SOM characterisation across a broad range of plant sources, degradation states and environmental conditions in peatlands and afforested peatlands using THM in the presence of TMAH. This allows an increased understanding of SOM storage and transformations during land use change, from pristine peatland to afforested peatland.

Background

Northern peatlands cover an area of around 350×106 ha, and store around one-third of global soil carbon (C) (Gorham, 1991) and as a result are very important carbon sinks. The afforestation of these carbon rich peatlands has been the largest land use change in Great Britain over the past 100 years, with 315,000 ha of shallow peatlands planted with coniferous forest (Hargreaves et al., 2003). However, the effect this may have on the carbon storage is unknown.

In order to obtain a clearer picture of the processes occurring after afforestation, it is vital to understand the range of both lignins and polyphenolic compounds (e.g. from peat mosses) present prior to the land use change. This will allow us to determine the role of aged peat moss phenolics on the current soil organic carbon, and be aware that the markers found in the pristine peat can be used as tracers within the afforested peat.

This project used thermally assisted hydrolysis and methylation (THM) in the presence of labelled and 13C-labelled tetramethylammonium hydroxide (TMAH) in order to identify intact lignin, demethylated lignin and non-lignin phenols.