Over 20% of Scotland’s land is classed as peatland. These organic rich soils provide many ecosystem services. One of their main functions is to act as a carbon storage. Scottish peatlands hold more than 1.6 billion tonnes of carbon and therefore healthy peatlands are key to our battle against climate change.
However, the majority of peatlands in Scotland are damaged due to land-use and climate change. Large scale investments (millions of pounds) are being made to restore peatlands, mostly by raising the water table. The hope is to kick-start the conditions suitable for peat formation. However, in order to determine whether these methods are working or not, we need to broaden their understanding by studying decomposition and peat formation at a molecular level.
Liquid-state NMR spectroscopy provides unique insights into the molecular composition of NOM. Standard proton and carbon-13 NMR experiments tell us what types of molecule are present in each sample. However, due to the sheer number of molecules, the signal overlap is substantial. In order stand a chance to characterise these mixtures, we require access to very high field NMR spectrometers. In the School of Chemistry in Edinburgh we have full access to an 800 MHz spectrometer. We use it to develop methodology aimed at characterising selected compound classes present in NOM.
Solid State NMR
A significant part of NOM consists of non-soluble material that needs to be investigated in solid-state. We are optimizing the use of solid-state NMR methods, including advanced editing techniques, to further advanced the molecular information contained in from NOM samples.
Ultra High Resolution Mass Spectrometry
Ultra-high resolution MS allows us to assign a molecular formula to thousands ionisable compound in NOM. This is particularly useful for looking at the changes occurring to the labile fraction of peat soils and assessing the molecular composition of peatlands in different conditions.
Natural Organic Matter (NOM) is main pool of carbon based molecules found in soil, aquatic and atmospheric systems.
Why bother with NOM? NOM plays a crucial role in many biogeochemical processes from determining the fate of contaminants such as heavy metals to carbon storage.
What do we want to know? In order to understand the many environmental processes at the molecular level, composition of NOM needs to be investigated. Despite their ubiquitous nature and importance the composition of NOM molecules remains elusive. This is mainly due to the fact that NOM is a complex mixture of thousands of molecules that cannot be separated by means of chromatography. The most promising tools for this task are advanced liquid-and solid-state NMR and high resolution mass spectrometry.
What is the Bell group doing? We use and develop new NMR and MS methodologies to unravel the composition of NOM and use this knowledge to help understand key questions regarding processes involving NOM. Currently our main focus is NOM of organic rich soils forming peatlands.