Climate-linked microbial interactions in green tide causing seaweed

SAHA_UPML23AN (Joint project with NRP DTP)

Climate-linked microbial interactions in green tide causing seaweed

SAHA_UPML23AN (Joint project with NRP DTP)

Project Description


Dr Mahasweta Saha (Plymouth Marine Laboratory) – contact me

Prof Jonathan Todd, Biological Science, University of East Anglia

Dr Frances Hopkins, Plymouth Marine Laboratory


Project background

Dimethylsulfoniopropionate (DMSP) is one of Earth’s most abundant organosulfur molecules and Ulva seaweeds, which cause green tides, are prolific DMSP producers. Ulva species produce DMSP as an anti-stress compound and can cleave DMSP to liberate the climate-cooling gas dimethylsulfide (DMS), but the precise role of DMSP in Ulva is unclear. Furthermore, DMSP released by Ulva into the environment has roles in signalling and recruiting beneficial bacteria, which use DMSP as a nutrient and facilitate further DMS production.

This project will use multidisciplinary techniques to explore how and why Ulva makes and degrades DMSP and to study its interactions with associated bacteria that utilise the DMSP Ulva produces.


You will use oceanographic sampling to establish a laboratory stock of Ulva lactuca which you will learn to cultivate under varied environmental conditions at Plymouth Marine Laboratory (PML) with Saha. Analytical techniques, e.g. chromatography and mass spectroscopy, will be used to quantify Ulva DMSP synthesis and catabolic rates, with training provided by Hopkins at PML. At UEA you will characterise the expression and activity, respectively, of key Ulva DMSP synthesis and lyase genes/enzymes by PCR-based techniques and enzymology with Todd. You will be trained by Todd in cutting-edge molecular ecology, e.g. DNA-stable isotope probing and metagenomics, to identify microbes that utilise DMSP for carbon from Ulva samples and their catabolic pathways. Finally, culture-dependent molecular microbiology will be used to characterise model DMSP-degrading microbes isolated from Ulva. This project will represent the first molecular microbiological study of organosulfur cycling by green tide-causing Ulva that produces exceptionally high DMSP levels.



You will receive exceptional training at PML and UEA in molecular ecology and microbiology, bioinformatics, analytical chemistry, coastal marine fieldwork and in writing high impact publications. You will learn good laboratory practice, quality assurance, and receive health and safety training. You will present your findings at weekly team meetings, high-profile international scientific conferences, and in peer-reviewed scientific publications and your PhD thesis.

This project is jointly funded with the BBSRC NRP DTP

Person specification

We require a committed, pro-active, and self-reliant candidate keen to master a wide range of techniques. Experience in some of the key components including chemistry is desirable.


  • Saha, M., Rempt, M., Gebser, B., Grueneberg, J., Pohnert, G. & Weinberger, F. (2012) Dimethylsulphopropionate (DMSP) and proline from the surface of the brown alga Fucus vesiculosus inhibit bacterial attachment. Biofouling 28: 593–604.
  • Jingli Liu, Chun-Xu Xue, Jinyan Wang, Andrew T. Crombie, Ornella Carrión, Andrew W. B. Johnston, J. Colin Murrell, Ji Liu, Yanfen Zheng, Xiao-Hua Zhang, Jonathan D. Todd. (2022) Oceanospirillales containing the DMSP lyase DddD are key utilisers of carbon from DMSP in coastal seawater. Microbiome 10 (110)
  • Curson ARJ, Williams BT, Pinchbeck BJ, Sims LP, Martínez AB, Rivera PPL, Kumaresan D, Mercadé E, Spurgin LG, Carrión O, Moxon S, Cattolico RA, Kuzhiumparambil U, Guagliardo P, Clode PL, Raina JB, Todd JD. (2018). DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton. Nature Microbiology 4: 430-439.
  • Curson ARJ, Todd, JD, Sullivan MJ and Johnston AWB (2011). Catabolism of dimethylsulfoniopropionate: microorganisms, enzymes and genes. Nature Reviews Microbiology 9: 849-859.
  • Hopkins, F. E., Nightingale, P. D., Stephens, J. A., Moore, C. M., Richier, S., Cripps, G. L., & Archer, S. D. (2020). A meta-analysis of microcosm experiments shows that dimethyl sulfide (DMS) production in polar waters is insensitive to ocean acidification. Biogeosciences 17, 163–186.

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 11th January 2023.
  • Successful candidates who meet UKRI’s eligibility criteria will be awarded a NERC studentship, which covers fees, stipend (£17,668 p.a. for 2022/23) and research funding. International applicants are eligible for fully-funded ARIES studentships including fees. Please note however that ARIES funding does not cover additional costs associated with relocation to, and living in, the UK.
  • 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.

Applications are open

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