Prof Rolf Aalto, Department of Geography, College of Life and Environmental Sciences, University of Exeter
Prof Andrew Nicholas, Department of Geography, College of Life and Environmental Sciences, University of Exeter
Dr Michael Singer, School of Earth and Ocean Sciences, Cardiff University
Location: University of Exeter, Streatham Campus, Exeter, EX4 4QJ
This project is one of a number that are in competition for funding from the NERC GW4+ Doctoral Training Partnership (GW4+ DTP). The GW4+ DTP consists of the GW4 Alliance of research-intensive universities: the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus five unique and prestigious Research Organisation partners: British Antarctic Survey, British Geological Survey, Centre for Ecology & Hydrology, the Natural History Museum and Plymouth Marine Laboratory. The partnership aims to provide a broad training in the Earth, Environmental and Life sciences, designed to train tomorrow’s leaders in scientific research, business, technology and policy-making. For further details about the programme please see http://nercgw4plus.ac.uk/
For eligible successful applicants, the studentships comprises:
- A stipend for 3.5 years (currently £15,009 p.a. for 2019/20) in line with UK Research and Innovation rates
- Payment of university tuition fees;
- A research budget of £11,000 for an international conference, lab, field and research expenses;
- A training budget of £3,250 for specialist training courses and expenses.
- Travel and accommodation is covered for all compulsory DTP cohort events
- No course fees for courses run by the DTP
We are currently advertising projects for a total of 10 studentships at the University of Exeter
The vast majority of organic carbon (C-org) is stored in sediments and sedimentary rocks (these stores exceed the C-org in the atmosphere, biosphere, and ocean by a factor of > 1000x). For example, large river systems transport and bury huge quantities of C-org throughout giant lowland basins that form some of the largest sedimentary deposits on Earth. Such deposits may be laid down in coordination with ENSO-driven flooding (Aalto et al., 2003), or typhoons that are shifting as climate changes (Darby et al, 2016). Riverine processes and C fluxes may therefore represent a significant player in Earth’s carbon cycle (Aufdenkampe et al., 2011), especially given that rising global sea levels may lead to accelerated sediment and carbon sequestration. Despite the potential significance of these processes, the mechanisms, rates and implications of C burial over annual to century timescales are poorly understood and quantified. This project will address these knowledge gaps.
Project Aims and Methods
This project will investigate carbon deposition in river sediment by measuring carbon concentrations for a large set of previously dated sediment cores collected across 1000s of kilometres of floodplains in the Amazon, the lower Mekong, Papua New Guinea, the Danube, and elsewhere. With all the project cores already in cold storage at Exeter, and all necessary lab equipment available to students, research can be focused and efficient in terms of producing datasets of lasting and likely global significance. Previous measurement of similar samples has led to important insights, such as the observation that the island of Papua New Guinea exports more sediment-associated carbon to the ocean than the entire Amazon basin (Alin et al., 2008). While making new measurements of carbon loading at Exeter, the student will also benefit from existing datasets and interdisciplinary collaborations with biogeochemists and geomorphologists in the USA and France.
The resulting lab data will allow carbon burial rates and fluxes to be quantified across a range of major river basins, and will be used to test and constrain existing models (developed at Exeter) of C cycling and sequestration in fluvial environments. This will lead to novel insights into the significant role that river floodplain deposits may play in modulating Earth’s carbon cycle.
References / Background reading list
R Aalto, L Maurice-Bourgoin, T Dunne, DR Montgomery, CA Nittrouer, JL Guyot, 2003, Episodic sediment accumulation on Amazonian flood plains influenced by El Nino/Southern Oscillation, Nature, 425, 493-407.
SR Alin, R Aalto, MA Goni, JE Richey, WE Dietrich, 2008, Biogeochemical characterization of carbon sources in the Strickland and Fly rivers, Papua New Guinea, JGR Earth Surface, 113, F1.
AK Aufdenkampe, E Mayorga, PA Raymond, JM Melack, SC Doney, SR Alin, RE Aalto, K Yoo, 2011, Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere, Frontiers in Ecology and the Environment, 9, 1, 53-60.
SE Darby, CR Hackney, J Leyland, M Kummu, H Lauri, DR Parsons, JL Best, AP Nicholas, R Aalto, 2016, Fluvial sediment supply to a mega-delta reduced by shifting tropical-cyclone activity, Nature, 539, 276.