PhD Studentship: Methane on the Move Investigating Benthic and Planktonic Drivers of Methanotroph Ecology in Lakes

Lakes are dynamic methane sources where both benthic and pelagic processes shape net emissions. Sediments are the dominant methane producers, but growing evidence shows that phytoplankton can generate methane under oxic conditions, particularly under phosphorus limitation via phosphonate degradation by Bacteria. Methanotrophs mediate both sources, consuming methane at the sediment–water interface, in the oxycline, and around algal particles. Their activity is shaped by cross-feeding interactions with heterotrophs, nitrifiers, and sulfur oxidisers, yet the ecological links between benthic and planktonic methane sources and methanotroph communities remain unresolved.

This PhD will examine how methanotrophs integrate methane derived from sediments and plankton. Field surveys in the UKCEH Cumbrian Lakes (Windermere, Esthwaite, Blelham) and Lakes Tour campaigns (20 lakes across a trophic gradient) will capture seasonal shifts in phytoplankton, benthic communities, and methanotrophs, using amplicon sequencing, metatranscriptomics and metagenomics to link taxa and functional genes (pmoA, mmoX, phnJ). Depth-resolved analyses will reveal which methanotroph taxa align more strongly with sediment fluxes, phytoplankton biomass, or both. This combined with analysis of sediment derived communities will assess how present and past methanotroph taxa have changed in response to nutrient inputs into freshwater lakes and with other changing environmental conditions.

Lab experiments will move from association to mechanism. Methanotrophs will be enriched and isolated from lake water and sediment. Co-cultures will test whether phytoplankton exudates, benthic substrates, or phosphorus-limited conditions sustain methanotroph growth. Stable isotope probing with ¹³CH₄ will identify active methanotroph taxa, while ¹³CO₂ incubations with phytoplankton will test whether phytoplankton-derived methane is assimilated into methanotroph biomass. Together, these approaches will clarify how benthic and pelagic carbon pathways intersect through the methane biofilter, with implications for predicting methane emissions in a changing climate.

For further information on this project and details of how to apply, please click on the 'Apply' button above.

Further information on how to apply for a CENTA studentship can be found on the CENTA website: https://centa.ac.uk/apply/

Please be aware that the successful applicant would be registered at the University of Birmingham but would be based at the UK Centre for Ecology and Hydrology.

References:

This project is offered through the CENTA3 DLA, funded by the Natural Environment Research Council (NERC). Funding covers: annual stipend, tuition fees (at home-fee level), Research Training Support Grant.

Academic requirements: at least a 2:1 at UK BSc level or a pass at UK MSc level or equivalent.

International students are eligible for studentships to a maximum of 30% of the cohort. Funding does not cover any additional costs relating to moving or residing in the UK. International applicants must fulfil the University of Birmingham’s international student entry requirements, including English language. Further information: https://www.birmingham.ac.uk/postgraduate/pgt/requirements-pgt/international/index.aspx.

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