Impacts of weathering, redox cycling and microbial activity on the formation of kaolinite (china clay). PhD in Mining and Minerals Engineering (NERC GW4 + DTP) Ref: 3670
About the award
Dr Laura Newsome, Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter
Dr Heather Buss, School of Earth Sciences, University of Bristol
Dr Javier Cuadros, Department of Earth Sciences, Natural History Museum
Location: University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE
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 accomodation 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
Students who are resident in EU countries are eligible for the full award on the same basis as UK residents. Applicants resident outside of the EU (classed as International for tuition fee purposes) are not eligible for DTP funding. Residency rules are complex and if you have not been resident in the UK or EU for the 3 years prior to the start of the studentship, please apply and we will check eligibility upon shortlisting.
Do microbes help make china clay? Kaolin minerals are very important economic resources; so much so that china clay has sometimes been referred to as “white gold”. Understanding how kaolin minerals form and behave in the environment is important because not only are they valuable economically, they also transport metals and nutrients to the ocean, can be used to remediate pollutants, and have been identified on the surface of Mars. Large kaolin deposits form from granites, either by hydrothermal alteration or by surface weathering in areas with temperate climates and high rainfall. Kaolin minerals also form in soils in intensely weathering environments. Kaolinization is thought to be triggered by the oxidation of iron(II) in biotite, and this has been linked to the activity of iron(II)-oxidising microorganisms. However, microbial iron(II) oxidation at neutral pH tends to occur in relatively narrow zones of redox interfaces rather than over tens of metres, which raises questions about its significance in economic kaolin deposits. This project will test the hypothesis that microbial redox cycling of iron contributes to kaolin formation in near surface environments, and therefore stimulating microbial redox cycling will increase the rate of kaolinization.
Project Aims and Methods
This project will characterise the conditions under which kaolinite forms during surface weathering of granites, investigate the role of microbial iron cycling and how this influences the rate of reaction, and consider how these processes can be enhanced to improve the kaolinization of low-grade materials by:
•Studying the composition of microbial communities in kaolin deposits (including those currently mined by Imerys at St Austell) using high throughput DNA sequencing.
•Observing the role of microorganisms in kaolinite formation and weathering by performing laboratory experiments with pure mineral phases and cultures of iron-reducing and iron-oxidising bacteria.
•Simulating weathering by performing sediment microcosm redox cycling experiments to observe the behaviour of kaolinite during biogeochemical cycling.
There will be the potential for fieldwork to collect samples from different kaolin deposits beyond the UK. Flexibilities exist for the student to be involved in experimental design and in decisions regarding choice of analytical techniques. We envisage the student will characterise samples using X-ray diffraction, scanning electron microscopy and synchrotron X-ray techniques (www.diamond.ac.uk/Home/About.html).
Overall this interdisciplinary research project links geology and biology to provide fundamental insights into the role of microbes in the formation of a highly important mineral resource. It will provide the student with a deep understanding of biogeochemical cycling, weathering, and environmental mineralogy, as well as providing skills for pursuing careers in academia, environmental consulting, industry or the public sector.
Mining of the St Austell china clay deposit on a kilometre scale (© Imerys)
Micron scale microbe-mineral interactions using Scanning Electron Microscopy (© L. Newsome)
The ideal candidate will have a strong background (preferably MSc-level) in a relevant discipline, such as Geoscience, Geology, Microbiology, Molecular Biology, Environmental Chemistry, or Biology, with a particular interest in environmental geomicrobiology and geochemistry.
Imerys is the world leader in mineral-based specialities and operates various kaolinite mines including at St Austell. Their support would enhance this project by providing access to samples of kaolin minerals and mineral waste and liaison with industry contacts. The student would be able to interact with Imerys during the project to get an industry perspective, and there is the potential for a summer secondment.
The student will be supervised by experts in geomicrobiology and environmental mineralogy (Newsome), biogeochemical weathering (Buss), and clay mineralogy and geochemistry (Cuadros). This interdisciplinary research project will involve training in laboratory techniques such as mineralogical characterisation, microbiological work and geochemical monitoring. The student will be supported to participate in NERC GW4+ DTP training courses (e.g., statistics, bioinformatics, computer programming) and will have access to a wealth of training opportunities from the University of Exeter’s Researcher Development Programme, which offers a wide range of workshops, seminars, and online resources covering topics such as project management, writing, resilience and wellbeing, public engagement, research ethics, IT skills, careers prep, data sharing, and teaching. Funding is provided for the student to present their research at a major international conference such as Goldschmidt or ISME, and the student will be encouraged to apply for travel grants to support further travel opportunities.
References / Background reading list
Cuadros J., Afsin B., Jadubansa P., Ardakani M., Ascaso C. and Wierzchos J. (2013) Microbial and inorganic control on the composition of clay from volcanic glass alteration experiments. Am. Mineral. 98, 319-334. http://dx.doi.org/10.2138/am.2013.4272
Li G. L., Zhou C. H., Fiore S. and Yu W. H. (2019) Interactions between microorganisms and clay minerals: New insights and broader applications. Appl. Clay Sci. 177, 91–113. https://doi.org/10.1016/j.clay.2019.04.025
Minyard M. L., Bruns M. A., Liermann L. J., Buss H. L. and Brantley S. L. (2012) Bacterial associations with weathering minerals at the regolith-bedrock interface, Luquillo Experimental Forest, Puerto Rico. Geomicrobiol. J. 29, 792–803. http://dx.doi.org/10.1080/01490451.2011.619640
Applicants should have obtained, or be about to obtain, a First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK. Applicants with a Lower Second Class degree will be considered if they also have Master’s degree. Applicants with a minimum of Upper Second Class degree and significant relevant non-academic experience are encouraged to apply.
All applicants would need to meet our English language requirements by the start of the project http://www.exeter.ac.uk/postgraduate/apply/english/.
How to apply
In the application process you will be asked to upload several documents. Please note our preferred format is PDF, each file named with your surname and the name of the document, eg. “Smith – CV.pdf”, “Smith – Cover Letter.pdf”, “Smith – Transcript.pdf”.
- Letter of application outlining your academic interests, prior research experience and reasons for wishing to undertake the project.
- Transcript(s) giving full details of subjects studied and grades/marks obtained. This should be an interim transcript if you are still studying.
- If you are not a national of a majority English-speaking country you will need to submit evidence of your current proficiency in English.
You will be asked to name 2 referees as part of the application process, however we will not expect receipt of references until after the shortlisting stage. Your referees should not be from the prospective supervisory team.
If you are shortlisted for interview, please ensure that your two academic referees email their references to the firstname.lastname@example.org, 7 days prior to the interview dates. Please note that we will not be contacting referees to request references, you must arrange for them to be submitted to us by the deadline.
References should be submitted by your referees to us directly in the form of a letter. Referees must email their references to us from their institutional email accounts. We cannot accept references from personal/private email accounts, unless it is a scanned document on institutional headed paper and signed by the referee.
All application documents must be submitted in English. Certified translated copies of academic qualifications must also be provided.
The closing date for applications is 1600 hours GMT Monday 6 January 2020. Interviews will be held between 10 and 21 February 2020. For more information about the NERC GW4+ DPT please visit https://nercgw4plus.ac.uk
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|Application deadline:||6th January 2020|
|Value:||£15,009 per annum for 2019-20|
|Duration of award:||per year|
|Contact: PGR Enquiriesfirstname.lastname@example.org|