How does the unusual metabolism of cable bacteria impact iron and sulfur cycling in coastal sediments.


How does the unusual metabolism of cable bacteria impact iron and sulfur cycling in coastal sediments.


Project Description


Prof. Thomas Clarke (University of East Anglia, School of Biological Sciences)

Prof. Jonathan Todd, University of East Anglia, School of Biological Sciences

Prof. Julea Butt, University of East Anglia, School of Chemistry


Project background

Microbes known as cable bacteria grow vertically in 10 cm filaments that span both the anoxic and oxic zones of aquatic sediments.  They uniquely make energy by coupling the oxidation of reduced compounds in the anoxic zone to the reduction of oxygen, and so are not restricted by the availability of oxidised compounds in the anoxic zone (1). This likely influences the physiology and metabolism of the local microbial community as well as biogeochemical cycling, but the nature of these effects have not yet been investigated.  This is because these organisms were only identified by our collaborators at Aarhus university a decade ago.  Despite recent advances, the physiology and environmental impact of these organisms is poorly understood.  In our pilot studies we show the cable bacterium Candidatus electrothrix to be relatively abundant in diverse iron and sulfur rich coastal sediments throughout the year.  These abundances fluctuate over seasons, and are consistent with fluctuations observed with the relative abundances of iron and sulfur species (2).

Research methodology

The student will establish methods to enrich cable bacteria in the UK, and to measure their abundance and activity in situ, supported by our collaborators who are the world experts in this field.  They will study the relative abundance of different chemical species in sediments enriched for cable bacteria with sediments that have not been enriched.  This will allow the impact of these organisms to be accurately addressed across a range of scientific areas, including changes in distribution of the redox active elemental species such as nitrogen and sulfur and the metagenomic distribution of other micro-organisms (3).


The student will spend 12 months at Aarhus university learning to work with cable bacteria, incl. how to culture them and to determine their activity.  They will receive training in environmental analysis of metals and their different redox states as well as differentiating between different sulfur species in order to determine how the sediment composition is affected.  They will learn environmental DNA extraction techniques and metagenomic sequencing methods to determine how the microbiome is affected by the active metabolism of these organisms.

Person specification

A person with a degree in Microbiology or related discipline is required.  Experience with field work is desirable.  This project offers the opportunity to live and study at Aarhus univerisity for up to a year.


  • On the evolution and physiology of cable bacteria. Kjeldsen KU et al. Proc Natl Acad Sci U S A. (2019) 116:19116-19125
  • Bacteria are important dimethylsulfoniopropionate producers in coastal sediments Williams, B. T et al. Nature Microbiology. (2019) 4, p.1815-1825
  • Role of multiheme cytochromes involved in extracellular anaerobic respiration in bacteria Edwards MJ et al. (2020) Protein Sci. 2019. doi: 10.1002/pro.3787

Key Information

  • This project has been shortlisted for funding by the ARIES NERC DTP and will start on 1st October 2023. The closing date for applications is 23:59 on 19th May 2023.
  • Successful candidates who meet UKRI’s eligibility criteria will be awarded a NERC studentship, which covers fees, stipend (£18,622 p.a. for 2023/24) and research funding. Please note that all international awards have been made for our programme for 2023 so we will not be accepting applications from international candidates,
  • ARIES students benefit from bespoke graduate training and ARIES provides £2,500 to every student for access to external training, travel and conferences, on top of all Research Costs associated with the project. Excellent applicants from quantitative disciplines with limited experience in environmental sciences may be considered for an additional 3-month stipend to take advanced-level courses.
  • ARIES is committed to equality, diversity, widening participation and inclusion in all areas of its operation. We encourage enquiries and applications from all sections of the community regardless of gender, ethnicity, disability, age, sexual orientation and transgender status. Academic qualifications are considered alongside non-academic experience, and our recruitment process considers potential with the same weighting as past experience.
  • All ARIES studentships may be undertaken on a part-time or full-time basis, visa requirements notwithstanding
  • For further information, please contact the supervisor. To apply for this Studentship follow the instructions at the bottom of the page or click the 'apply now' link.
  • ARIES is required by our funders to collect Equality and Diversity Information from all of our applicants. The information you provide will be used solely for monitoring and statistical purposes; it will remain confidential, and will be stored on the UEA sharepoint server. Data will not be shared with those involved in making decisions on the award of Studentships, and will have no influence on the success of your application. It will only be shared outside of this group in an anonymised and aggregated form. You will be ask to complete the form by the University to which you apply.

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