Prof Tim Lenton, Department of Geography, College of Life and Environmental Sciences, University of Exeter
Dr Ute Schuster, Department of Geography, College of Life and Environmental Sciences, University of Exeter
Dr Paul Halloran, Department of Geography, College of Life and Environmental Sciences, University of Exeter
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
Resilience describes how fast a system recovers from perturbations. The Earth’s carbon cycle has been perturbed repeatedly in the past, and is being perturbed again now by human activities. Crucial questions are: How resilient is the Earth system to perturbation? Has its resilience changed over time? And if so, why?
Excess carbon dioxide added to the atmosphere-ocean system is buffered by the dissolution of carbonate sediments on land and on the seafloor and ultimately removed by the weathering of silicate rocks and re-deposition of carbonate sediments. An overlooked factor in this Earth system response is the relative exposure and erosion of carbonate sediments on land and their potential to enhance CO2 drawdown.
For example, large beds of Cretaceous carbonates (including chalk) have subsequently been uplifted and stand as readily weathered cliff face coastlines, outcrops and Karst/cave systems. This project will examine the contribution of enhanced carbonate weathering to accelerating recovery from past and present carbon cycle perturbations.
Project Aims and Methods
This project aims to quantify the contribution of enhanced carbonate weathering to Earth system resilience. Prospective students are encouraged to help design the project.
A proposed focus is: Did the uplift of large beds of Cretaceous chalk enhance Earth system resilience in response to the Paleocene-Eocene Thermal Maximum (PETM) 55 million years ago? And will it accelerate Earth system recovery from anthropogenic perturbation?
Potential methods include: The use of remote sensing and GIS to establish the present day global extent of chalk (and other carbonate) coastlines. Lab experiments to obtain rate information on erosion and/or chemical weathering rates. Field measurements to establish the alkalinity contribution of chalk cliff erosion. Refining of models of carbonate weathering with this information. Earth system modelling with GENIE to quantify the global impact of the weathering of uplifted carbonate (including chalk) platforms.
The project has a strong supervisory foundation: Lenton helped developed the GENIE model and its weathering module (Colbourn et al. 2015), which has been used to study carbon cycle perturbations, including the PETM (Gutjhar et al. 2017), and anthropogenic perturbation. Schuster is an expert in ocean carbon and carbonate chemistry (Schuster et al., 2013; Le Quere et al. 2018). Halloran has 3D modelling and paleo-proxy expertise (Rickaby and Halloran, 2005) and has worked extensively on the formation and dissolution of carbonate sediments (Iglesias-Rodriguez et al., 2008).
References / Background reading list
Colbourn, G., A. Ridgwell and T. M. Lenton (2015). "The time scale of the silicate weathering negative feedback on atmospheric CO2." Global Biogeochemical Cycles 29(5): 583-596.
Gutjahr, M., A. Ridgwell, P. F. Sexton, E. Anagnostou, P. N. Pearson, H. Pälike, R. D. Norris, E. Thomas and G. L. Foster (2017). "Very large release of mostly volcanic carbon during the Palaeocene–Eocene Thermal Maximum." Nature 548: 573.
Iglesias-Rodriguez*, M.D., P.R. Halloran* (*Co-lead Authors), et al. (2008). “Phytoplankton calcification in a high CO2 world.” Science 320: 336-340.
Le Quere, C., et al. (2018). “The Global carbon budget 2018.” Earth System Science Data 10: 2141-2194.
Rickaby, R.E.M. and P. Halloran (2005). “Cool La Niña during the warmth of the Pliocene?” Science 307: 1948-1952.
Schuster, U., et al. (2013) “An assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009.” Biogeosciences 10: 607-627, doi:10.5194/bg-10-607-2013.