David Johnson

This PhD project, based at The University of Manchester, investigates the mechanisms of carbon cycling within microbial communities inhabiting extreme geothermal springs. These unique environments, characterized by low phylogenetic diversity and minimal organic carbon input, serve as natural laboratories for studying efficient CO2-driven carbon cycling. The research aims to harness these microbial processes for innovative CO2 capture and bioconversion technologies that could surpass current methods. The project employs advanced stable isotope tracer experiments (using 13C) to track CO2 utilization by various microbial taxa. The central hypothesis is that CO2-driven carbon cycling is achieved through a metabolic division of labour among community members, which can be elucidated using stable isotope probing combined with multi-omics analyses. System-level measurements will be integrated with strain-resolved metagenomics, conducted by other team members, to provide a comprehensive understanding of the metabolic potential within these communities. Fieldwork will be conducted in geothermal springs in Iceland, complemented by controlled laboratory experiments in Manchester. The successful candidate will join a multidisciplinary team supported by a £5.4M BBSRC sLoLa grant, offering extensive opportunities for training and collaboration. Direct training will be provided in isotopic techniques, -omics approaches, and microbial ecology. Supervisory Team: Dr Sophie Nixon and Professor Andrew Pitt (The University of Manchester), Professor David Johnson (Lancaster University). Eligibility: Applicants should hold or expect to achieve at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering discipline. English language certification is required if applicable. The university encourages applications from diverse backgrounds and supports flexible study arrangements. Funding: The 3.5-year PhD studentship is open to both Home (UK) and overseas students. It includes a tax-free stipend at the UKRI rate (£20,780 for 2025/26, subject to annual uplift) and full tuition fee coverage. The stipend is expected to increase annually. Application Process: Apply online via the University of Manchester portal. Early application is recommended as the advert may close before the deadline. Applicants must submit all required documents, including transcripts, CV, supporting statement, and referee details. Incomplete applications will not be considered. Contact the supervisor before applying to discuss your motivation and background. Deadline: 30 April 2026. The start date is October 2026. For further information or application queries, contact the admissions team at [email protected].