Processing and fluxes of DOM in peat-pools and lochans

Peatlands are the UKs largest carbon store, yet they have been largely degraded by poor land management. Combined with predicted increased likelihood of extreme weather events (e.g. droughts and wildfire) means that we now have a large pool of carbon vulnerable to loss through release of CO2/CH4 to the atmosphere, or erosion and transport as Dissolved Organic Carbon (DOC) into the aquatic continuum. The paradigm that fluvial networks simply transport terrestrial derived Dissolved Organic Matter (DOM) to the ocean is now firmly dismissed, with rivers and lakes now recognised as biogeochemical hotspots for the breakdown of DOC and the outgassing of CO2/CH4 to the atmosphere. Peat-pools and lochans are key zones for the aquatic processing of DOM in its journey through the catchment, yet little is known about DOM fluxes into and out of these systems or the drivers behind decomposition within them.

This PhD will address this knowledge gap, aiming to further our understanding of biogeochemical processing of peat-derived DOM as it enters the aquatic systems. Furthermore, quantifying the relative importance of photochemical reactions and biochemical degradation in the processing of DOM in peat-pools will aid our understanding of how they may respond to predicted increases of environmental stress such as drought and wildfires. Lastly, contextualising these rates and processes in the peat-pools of northern Scotland will begin to expand our knowledge of how important these aquatic systems are for the initial stages in degradation of peat-derived DOM.