Project highlights

  • Investigating marine ecosystem responses to climate and environmental change 
  • Become an expert in a major group of marine phytoplankton 
  • Work across disciplines – biology, climate science, ecology, geology 


Phytoplankton – single cellular organisms that photosynthesise in the surface ocean – are the base of the open ocean marine food chain. In the mid-to-high latitude oceans phytoplankton growth is often dominated by rapid cell growth over a large area through spring and early summer, so called phytoplankton ‘blooms’. Although these blooms consist of single celled organisms, they reach such abundances as to be observable from space (Figure 1). This rapid growth of phytoplankton cells, with their uptake of carbon from the oceans by photosynthesis, plays a major role in both the ocean carbon cycle and marine food chains. 

This project will focus on a dominant group of marine eukaryotic phytoplankton, the coccolithophores, that are unusual in producing a calcium carbonate external cell covering (coccoliths). The production of a biomineral makes them even more significant in terms of carbon cycling, but also allows for changes in bloom dynamics to be traced back through time using the sedimentary record of coccoliths. This record reveals an intriguing pattern of alternating dominance between two major groups of coccolithophores during different recent warm “inter-glacial” climate stages. The cause of these variations are poorly understood, even though they are important for ecoysystems and the carbon cycle because one group is relatively large and heavily calcified (Coccolithus pelagicus) whilst the other is relatively small and lightly calcified (Gephyrocapsa species). Both groups live in the modern North Atlantic and their changing abundance and species ranges with climate change is an important component of the future open ocean ecosystem dynamics. 

The project aims to combine understandings of modern physiology, with climate modelling and reconstructions of coccolithophore assemblages through recent inter-glacial climates to understand the temperature, nutrient and salinity controls on the dynamics species dominance. With this understanding, the student will contribute to improving modern ecosystem models that include coccolithophore functional groups and are being used in the prediction of future ecosystem change. 

This figure shows a satellite image of a region of the North Atlantic Ocean surrounding Iceland. Within a blue-green background there are clear white swirling and filamentous structures across the image that represent strongly reflective patches of the surface ocean. These reflective areas are caused by the presence of high concentrations of coccolithophore algae in the surface ocean.

Figure 1: This near-true colour MODIS satellite image shows a coccolithophore (phytoplankton) bloom in the Iceland Basin. Visible are the patches and filamentous structures of the bloom. The image is a composite for the period July 5-11, 2007. NEODAAS/PML 

CENTA Flagship

This is a CENTA Flagship Project


University of Birmingham


  • Organisms and Ecosystems


Project investigator

Tom Dunkley Jones, University of Birmingham, [email protected]


Glen Wheeler (MBA)

Kirsty Edgar

Melanie Leng (BGS, [email protected])

How to apply


The project has three components. 

  1. A review of the biology, physiology, and bloom dynamics of the dominant North Atlantic coccolithophore species (Tom Dunkley Jones, Glen Wheeler) 
  1. The reconstruction of coccolithophore communities and surface ocean conditions in the Iceland Basin and Greenland Margin from key warm interglacial periods using newly recovered sediment records from International Ocean Discovery Program Expedition 395 (June-July 2023) (Tom Dunkley Jones; Melanie Leng). This will include phytoplankton community analyses (Tom Dunkley Jones) and isotopic analyses of plankton carbonates (Melanie Leng). 
  1. The integration of climate proxy and climate model reconstructions of these intervals to generate a niche model for Coccolithus pelagicus and Gephyrocapsa that can inform modern ecosystem models (Kirsty Edgar) 

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.  

The student will receive unique training and research development through project partners at the Marine Biological Association and the British Geological Survey, but also within the international framework of IODP Expedition 395 Science Party. Dr Wheeler (MBA) will host the student for training in modern plankton biology and physiology. Prof Leng will host the student at the NERC National Environmental Isotope Facility (NEIF) at the British Geological Survey, providing world-leading training in stable isotope analyses. While host supervisors (Prof Dunkley Jones and Dr Edgar) are international experts in the taxonomy of oceanic plankton and their use to tackle questions of climate, ecosystem and environmental change. 

Partners and collaboration

The project has two key partners: first Dr Glen Wheeler (MBA; who is a world expert on the cell physiology of marine phytoplankton, including the responses of coccolithophore algae to global change. Glen’s expertise will be key in building a conceptual framework for understanding species trade-offs to environmental change in the North Atlantic. The second partner is Prof. Melanie Leng (, who is the BGS Chief Scientist for environmental change and expert in stable isotope geochemistry. Both Melanie and Glen will host the student on placements at MBA and BGS to undertake relevant components of the research project. 

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here: 

For any enquiries related to this project please contact Tom Dunkley Jones, [email protected]

To apply to this project: 

  • You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024. 
  • You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities. 
  • Please submit your application and complete the host institution application process via: Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form.  Please quote CENTA 2024-B12  when completing the application form. 

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024. 

Possible timeline

Year 1

Review of the biology, physiology, and bloom dynamics of the dominant North Atlantic coccolithophore species (MBA); introduction to species identification and initial assemblage data collection (UoB).

Year 2

Coccolithophore assemblage and climate proxy climate data collection (UoB, BGS). Attend and contribute to IODP Expedition 395 science meeting in Cyprus. 

Year 3

Compilation of assemblage data and development of niche and trait modelling, integrating both climate proxy and climate model data (UoB, MBA). Submission of publications and thesis. 

Further reading

Cerfonteyn, M. et al. 2023. The distribution and diversity of eukaryotic phytoplankton in the Icelandic marine environment. Sci Rep 13, 8519, doi:10.1038/s41598-023-35537-2 (2023). 

Baumann, K., Andruleit, H. & Samtleben, C. 2000. Coccolithophores in the Nordic Seas: comparison of living communities with surface sediment assemblages. Deep-Sea Research Part II 47, 1743-1772, doi:10.1016/S0967-0645(00)00005-9.