PhD: The Effect of Sediment-Seawater Interaction on Ocean Alkalinity Enhancement (OAE) Efficiency University of Southampton in United Kingdom

Project Overview: This PhD project investigates the impact of Ocean Alkalinity Enhancement (OAE) on the carbon cycle in marine sediments, with a focus on its potential as a marine Carbon Dioxide Removal (mCDR) technique to help mitigate climate change. OAE is a promising approach for atmospheric CO2 removal, but its efficiency and side effects, particularly regarding sediment-seawater interactions, remain uncertain. The research aims to provide new constraints on how OAE affects natural sediment-derived alkalinity fluxes and the permanence of carbon storage through carbonate mineral formation.

Research Context: Achieving the Paris Agreement’s climate targets requires active CO2 removal and storage. Marine CDR techniques, such as OAE, are gaining attention for their potential scale and permanence, but knowledge gaps persist about their effectiveness and environmental impacts. Recent studies suggest that OAE’s sequestration potential may be reduced by suppressing natural alkalinity generation in sediments, which this project will address through a combination of laboratory experiments and fieldwork.

Methodology & Training: The student will join the Marine Biogeochemistry Group at the University of Southampton’s School of Ocean and Earth Sciences, with access to state-of-the-art facilities. Training includes: (i) field collection of water and sediment samples from high-alkalinity coastal sites in the UK, Germany, and Croatia; (ii) laboratory experiments to assess sediment-seawater interactions and secondary mineralisation; (iii) analysis of carbonate parameters, trace elements, and isotopic ratios using advanced mass spectrometry techniques (ICP-MS, TIMS, MC-ICP-MS); and (iv) geochemical modelling with PHREEQC and CO2SYS. The project is supported by the IGNITE programme, offering comprehensive personal and professional development and opportunities for interdisciplinary collaboration.

Supervision & Collaboration: The supervisory team includes Dr C Pearce, Prof R James, Dr FD Deng, and Dr S Fowell, with additional input from CASE partner Vesta. The project is based in Southampton, with strong links to industry and policy partners.

Funding: The IGNITE Doctoral Landscape Award provides 3.5 years of funding (full- or part-time), including a tax-free stipend (£20,780 for 2025/26), Home tuition fees, and a Research Training Support Grant (£2,200/year). The University waives the difference between Home and International tuition fees, making the position open to both UK and international students (with limited international places).

Eligibility: Applicants should have a UK bachelor’s degree with upper second-class honours or higher (or international equivalent) in a relevant subject such as chemistry, earth sciences, or environmental sciences. English language proficiency (IELTS 6.5 overall, minimum 6.0 in all components, or equivalent) is required. The programme encourages applications from diverse backgrounds and offers a guaranteed interview scheme for qualifying UK applicants from racially minoritised groups.

Application Process: Applications must be submitted by 11:59pm on 8 January 2026 via the University of Southampton’s online portal. Prospective applicants are encouraged to contact the lead supervisor to discuss suitability before applying and may apply for up to two projects. For further details, see the official project page and university links provided.