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Award details

Investigating the role of low-oxygen adapted Prochlorococcus in ocean biogeochemical cycles, Biological Oceanography, Marine Science, Biogeochemistry – PhD (Funded) Ref: 4193

About the award


Academic Supervisors:

Dr Bob Brewin, University of Exeter

Dr Katy Sheen, University of Exeter

Dr Giorgio Dall’Olmo, Plymouth Marine Laboratory

Dr Shubha Sathyendranath, Plymouth Marine Laboratory

Professor Osvaldo Ulloa, Universidad de Concepción, Chile

The University of Exeter’s College of Life and Environmental Sciences is inviting applications for a fully-funded PhD studentship to commence in January 2022 or as soon as possible thereafter.  For eligible students the studentship will cover Home tuition fees plus an annual tax-free stipend of at least £15,609 for 3.5 years full-time, or pro rata for part-time study.  The student would be based in Geography in the College of Life and Environmental Sciences at the Penryn Campus in Cornwall.

Project Description

Oceanic phytoplankton help regulate the planetary cycling of major elements and compounds. The smallest and most abundant phytoplankton in the ocean is the unicellular cyanobacterium of the genus Prochlorococcus. It has been estimated that Prochlorococcus contribute between 10-50% of oceanic primary production, and thus play a critical role in the ocean carbon cycle. Though best known to thrive in a high light, high oxygen, and low nutrient environment, such as in the subtropical gyres, they are also known occupy anoxic regions in parts of the Pacific and Indian Oceans, characteristic of low light, low oxygen, and high nutrients. Less is known about the role these low-oxygen, low-light adapted Prochlorococcus play in planetary biogeochemical cycles, owing to difficulties observing them at synoptic scales. In recent years, however, there has been a proliferation of autonomous platforms capable of observing phytoplankton and oxygen dynamics at the base of the euphotic zone. Making use of autonomous platforms, such as Biogeochemical Argo floats, and combining data collected from these platforms with satellite observations and model output, this project will aim to quantify the global distribution of this low-oxygen, low-light adapted Prochlorococcus ecotype. By integrating these results with ship-based measurements on the rates of production of carbon and oxygen, the project will aim to quantify the contribution of this ecotype to global and regional primary production. With anoxic regions predicted to expand in the future, results from this work will have implications for how Prochlorococcus are responding to climate change. This PhD project is aligned to a UKRI-funded project investigating the response of phytoplankton to climate change. It will primarily be a computational project using existing datasets, but with scope to do some field work, and would suit a student with a background in marine science (or related discipline) and with some experience in computer coding.

This award provides annual funding to cover Home tuition fees and a tax-free stipend.  For students who pay Home tuition fees the award will cover the tuition fees in full, plus at least £15,609 per year tax-free stipend.  Students who pay international tuition fees are eligible to apply, but should note that the award will only provide payment for part of the international tuition fee and no stipend.

Entry requirements

Applicants for this studentship must have obtained, or be about to obtain, a First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK, in an appropriate area of science or technology.   The candidate will need to be self-motivated, pro-active and enthusiastic, with good numerical skills, ideally with some computer coding experience, and a scientific interest in biological oceanography.

If English is not your first language you will need to have achieved at least 6.5 in IELTS and no less than 6.0 in any section by the start of the project.  Alternative tests may be acceptable (see

How to apply

In the application process you will be asked to upload several documents. 
• CV
• 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)
• Names of two referees familiar with your academic work. You are not required to obtain references yourself. We will request references directly from your referees if you are shortlisted.
• If you are not a national of a majority English-speaking country you will need to submit evidence of your proficiency in English.

The closing date for applications is midnight on 15th October 2021.  Interviews will be held virtually in the week commencing 25th October 2021.

If you have any general enquiries about the application process please email or phone 0300 555 60 60 (UK callers) +44 (0) 1392 723044 (EU/International callers)  Project-specific queries should be directed to the main supervisor Dr Bob Brewin


Application deadline:15th October 2021
Value:Home tuition fees plus an annual tax-free stipend of at least £15,609 for 3.5 years full-time, or pro rata for part-time study.
Duration of award:per year
Contact: PGR Admissions