Organic matter cycling
Approximately twice as much carbon is stored in soils than is present in the atmosphere as CO2. Indeed, more carbon is stored in soil than in the atmosphere and above-ground biomass combined. Depending on land management and potential responses to future climate change terrestrial ecosystems can act as either a carbon source or a carbon sink. As well as the potential to store vast amounts of carbon, terrestrial ecosystems provide many ‘services’ that rely on processes where organic matter is transformed.
The availability of biologically accessible nitrogen is a limiting factor in the primary productivity of many ecosystems. Much is known about the cycling of inorganic forms of N in soils, however, the processing of organic forms of N (such as amino acids and proteins) has received much less attention. Understanding how these compounds behave in complex ecosystems such as soil, is vital if we are to develop models to help inform land management and agricultural practices
In the OGU we study soil organic matter processing by tracing the fate and transformations of rare stable isotopes including carbon (13C), nitrogen (15N) and deuterium (2H) in soils and sediments. Taking advantage of the high sensitivity detection afforded by isotope ratio mass spectrometry we are able to monitor soil microbial activity, elemental cycling and molecular transformations at environmentally relevant scales.
Applications that we principally focus on include CH4 cycling in mineral soils and natural wetlands, soil organic nitrogen utilisation, carbon release and transport from dung, and soil food web trophic level studies.
Maxfield, P.J., Hornibrook, E.R.C. and Evershed, R.P. (2008) Acute impact of agriculture on high-affinity methanotrophic bacterial populations. Environmental Microbiology 10, 1917-1924.