- Tackle outstanding fundamental ‘blue skies’ research challenge that seeks to quantify the links between the geomorphology of river systems and the biogeochemical processes within them to better understand the role of rivers in the carbon cycle and climate change
- Blend of experimental, field and remote sensing methods gives unrivalled skills development
- Significant opportunity for student to lead and develop the scope of the research
Disentangling the links and feedbacks between the physical (geomorphology) and biogeochemical drivers within rivers and floodplains represents a fundamental and outstanding challenge to all those involved in freshwater systems. Yet such knowledge is critical to understand the role of rivers and floodplains in the carbon cycle and how this links with climate change, both now and in the past.
In simplistic terms, river systems can behave on a continuum, the end members of which can have opposing impacts on the carbon cycle and hence climate; 1) if rivers are very active and flush any organic matter (e.g. early evolution of biofilms) and sediment to the oceans then this material gets buried and removed from the carbon cycle so reducing CO2 and lowering global temperature 2) with increasing fine sediment and organic matter retention within the river then they cease to act as inert pipes and will release greenhouse gases to the atmosphere so raising global temperature.
Understanding these fundamental processes matters if we are to make progress in resolving many outstanding ‘unknowns’. For example, it is well known that dam construction changes downstream flood regime, what is yet to be quantified is how this impacts on tree mortality and associated greenhouse gas emissions driven by changes to the water table, bank erosion and river stability (in a geomorphic sense). Similarly from a geological perspective the pre-vegetation role of rivers in global climate was presumably negligible, but as we moved from a largely inorganic river system to one with increasing organic components how did role of rivers change in linking terrestrial systems with atmospheric and marine?
The student will explore these questions using a combination of approaches to examine fundamentals relating to the role of life on river form and biogeochemistry. In doing so the student will examine how 1) the geomorphology (river and stream bed form) and 2) the biogeochemistry relating to the exchange of greenhouse gases is influenced indirectly through the influence of life on the physical properties of rivers. There remains the possibility of examining simplified and modified systems in the field (e.g. where deforestation has recently taken place) while also examining the simplest river sediment/microbial life interactions in the University’s state of the art Ecolab. The Ecolob is furnished with a range of flumes that allow model stream channels to be simulated. A range of other techniques including remote sensing, water chemistry assessment and biosphere atmosphere exchange of greenhouse gases are available to support the supplementary questions the student would like to answer.
Training and Skills
This project will require a candidate with broad ‘river science’ interests encompassing geomorphology and biogeochemistry. It is not necessary to be an expert in all these areas but a willingness to learn is essential. Full training will be provided in key aspects of the different disciplines including standard procedures for data collection and analysis.
Year 1: Undertake essential research training, develop key research questions that the project will tackle based on literature review and develop the methods required to get the data needed to meet project objectives.
Year 2: Based on work from year 1, design and conduct research to elucidate relationships and feedbacks operating between the physical, chemical and biological components of river systems.
Year 3: Data synthesis and analysis of data. Use this data to test hypotheses that can be applied widely to other sites and contexts. Poster presentation at a UK conference and an oral presentation at an international conference, paper production, thesis writing and submission.