New approaches to image dynamic sinking behaviour in marine phytoplankton

Second Supervisor (External Lead): Dr Glen Wheeler

Lead Supervisor (Director of Studies): Professor Alex Nimmo Smith

Third Supervisor: Dr James Clark 

Applications are invited for a 3.5-year PhD studentship with Marine Research Plymouth – a collaborative partnership between the University of Plymouth, the Plymouth Marine Laboratory and the Marine Biological Association. The studentship is due to start on 1 October 2024.

This project is one of four topics available for the studentship. We anticipate supporting one position, which will be allocated to the best combination of candidate and project as they emerge from interviews across the pool of available topics. Browse all available topics.

Plymouth has been at the forefront of global marine research for more than a century, and today it is home to the largest concentration of marine researchers in the UK. Come and join our vibrant community of marine PhD students.

The rate at which phytoplankton cells sink to the deep ocean plays a critical role in the global carbon cycle. Phytoplankton cells can actively control their orientation and buoyancy, indicating that biological processes play a major role in determining carbon export, although the factors controlling sinking rates remain poorly understood.

There are very few direct observations of sinking rates in individual phytoplankton cells, but new technologies allowing direct imaging of sinking phytoplankton cells are providing novel insight, demonstrating that sinking rates are highly dynamic and actively controlled. The ability to image these processes in single cells will provide unique insight into the biological processes that determine global carbon fluxes.

This project seeks to understand the biological processes that influence sinking rates in a range of marine phytoplankton. It will involve laboratory studies to image sinking behaviour in different phytoplankton groups, using both cultures and natural phytoplankton communities. We will examine how changes in environmental parameters (light, nutrients and temperature) influence these processes. In situ observations of phytoplankton orientation and sinking rates in the Western English Channel will be performed using a holographic imaging system that can be deployed from a research vessel. The experimental data will be used to develop a modified ecosystem model to examine how distinct sinking rates between phytoplankton groups could influence wider ecological processes such as carbon export.

The project will provide a unique blend of laboratory studies, fieldwork and theoretical analyses. The student will have the opportunity to learn multiple experimental techniques, including the development and application of novel imaging approaches. Further techniques will include phytoplankton culturing, field sampling, image analysis and ecosystem modelling. Full training will be provided by the supervisory team in the application of these approaches. 

Applicants should have a first or upper second class honours degree in an appropriate subject or a relevant masters qualification. The project is suitable for any candidate with an interest in developing and applying novel imaging technologies to study marine processes. A degree in marine biology, biology, ecology or a related subject would be most suitable. Skills in image analysis, handling large data sets and mathematical modelling are useful but prior knowledge is not essential.

Non-native English speakers must have an IELTS Academic score of 6.5 or above (with no less than 5.5 in any element) or equivalent.

The studentship is supported for 3.5 years and includes full home tuition fees plus a stipend at the 2024/25 rate (to be confirmed; compare the 2023/24 rate of £18,110 per annum). The last 6 months of the four-year registration period is a self-funded ‘writing-up’ period. The studentship will only fully fund those applicants who are eligible for home fees with relevant qualifications. Applicants normally required to cover international fees will have to cover the difference between the home and the international tuition fee rates (approximately £12,697 per annum at 2023/24 rate).

If you wish to discuss this project further informally, please contact Dr Glen Wheeler.

Shortlisted candidates will be informed as soon as possible after the deadline, with interviews likely to take place in the second half of February. We regret that we may not be able to respond to all applications. Applicants who have not received a response within six weeks of the closing date should consider that their application has been unsuccessful on this occasion.