Peatlands cover only 2.8% of the Earth but store 50% of the global soil carbon pool which exceeds the carbon stored in all other vegetation types, including the worlds’ forest. They also store 10% of the world’s freshwater. Peatland rivers are significant sources of fluvial carbon (as dissolved organic carbon (DOC), a component of organic matter) and concentrations of DOC in the northern hemisphere have doubled in the last 20 years. Climate change has been cited as one of the possible reasons for the observed increase, and prolonged drought is known to increase DOC production from peat, but the effect of climate change on organic matter composition is unknown. Predicted temperature increases are likely to affect the rate of the processing of organic matter in water, leading to an increase in greenhouse gas (GHG) emissions, which will further contribute to climate change. In-stream emissions from water bodies are under-represented in the Intergovernmental Panel on Climate Change (IPCC) reports. It is therefore essential to understand the relationship between climate and organic matter composition and processing to allow models of future climate change to include the potential for positive feedback as GHG emissions from water increase.
There are also implications of this increase in DOC concentration for water companies, as the water draining peatlands has high DOC and therefore dissolved organic matter (DOM) concentrations, resulting in highly coloured water. The water colour is closely monitored by water companies, as the levels allowed are strictly regulated, and the colour must be removed from the water. When water colour become too severe water companies have to invest tens of millions of pounds in capital for every new treatment plant, plus the additional expense of running those plants. For the IPCC, water companies, policy makers and society there is an urgent need to understand how climate change will affect the composition, processing and treatability of DOM, and the outcomes of this project will help to optimise water treatment performance to deal with threats posed by changes in DOM composition as a result of climate change.
This project will explore an interdisciplinary approach to quantify the effect of climate and land-use change on DOM composition and processing, and therefore potential GHG emissions.
This is an exciting and innovative project with the potential to make a big contribution to one of the most significant outstanding questions in peatland science: How will the composition changes in organic matter under future climate change scenarios and will this lead to a positive climate feedback? This PhD project is part of a larger ongoing research project funded by NERC and supported by several UK water companies, including Yorkshire Water, United Utilities, Northumbrian Water and Scottish Water. The project will be challenging but the student will be very well-supported. The research will use a range of field and laboratory experiments and the appointed student will benefit from a strong support network including a two-person supervisory team with expertise in all aspects of the project, especially in water chemistry and biology, with extensive experience of fieldwork and upland research. Fieldwork will be conducted in the UK uplands, and the findings will be of international relevance. The student will have access to excellent training and laboratory resources at the University of Leeds.