The Biogeochemistry of N-Osmolytes: From the Tropics to the Poles


The Biogeochemistry of N-Osmolytes: From the Tropics to the Poles


Project Description


Dr Ruth Airs (Plymouth Marine Laboratory) contact me

Professor Mark Fitzsimons (School of Geography, Earth and Environmental Sciences, University of Plymouth)

Dr Rachael Beale (Plymouth Marine Laboratory)

Project Background

Seawater houses a microscopic world of nature, essential to the life support for our planet. Osmolytes allow cells to survive in salt water and are environmentally relevant as they provide sources of nutrients for marine microbes. Degradation of N-osmolytes produces climate-active gases, such as methane and methylamines, with methylamines proposed to contribute to particle formation and growth in the atmosphere. Our understanding of environmental drivers of N-osmolytes is, however, very limited.  This PhD will test the following hypotheses (HP) by accessing samples and data from research expeditions and process studies performed by the international community across the globe and will make a step change in our understanding of N-osmolytes. HP1: Marine microbes rely most heavily on N-osmolytes under stress-conditions: low temperature, high or rapidly changing salinity, and/or low inorganic nutrient availability. HP2: The concentrations of N-osmolytes observed during process studies in different environments (polar, temperate, tropical) will have drivers dependent on a combination of the physicochemical conditions and the microbial population present.

During this PhD the candidate will:

1) Apply analytical chemistry (LC/MS-TOF) to measure N-osmolytes (glycine betaine, choline, trimethylamine N-oxide (TMAO)) in samples collected from polar, temperate and tropical field campaigns.

2) Use accompanying spatial and temporal process study data (e.g. microbial composition, physico-chemical properties) to test hypotheses in different environments

3) Design and carry out their own experimental sampling program on the PICCOLO cruise in the Weddel Sea, Antarctica.


This PhD includes training in seagoing research, analytical chemistry, scientific data analysis, scientific writing and engagement with a network of international collaborators. You will present your work at national and international conferences and enjoy a dynamic research environment at PML, as part of a PhD co-hort. You will receive training in health and safety processes certified to ISO45001, and mental health awareness. You will access a broad range of transferable skills training through ARIES.

This studentship will be based at the Plymouth Marine Laboratory, and registered at the University of Plymouth.

Person Specification

You should have a degree in the biological, chemical or environmental sciences, an excellent work ethic, good attention to detail and communication skills. Relevant analytical skills and an appreciation of algae would be ideal.


  • 1. Dall’Osto M, Airs RL, Beale R, Fitzsimons MF. et al. 2019. Simultaneous detection of Alkylamines in the Surface Ocean and Atmosphere of the Antarctic Sympagic Environment. ACS Earth and Space Chemistry 3(5), 854-862
  • 2. Dall’Osto M, …, Airs RL, Beale R, Fitzsimons MF, et al., 2017. Antarctic sea ice region as a source of biogenic nitrogen in aerosols. Scientific Reports 7(1), 6047.
  • 3. Beale R and Airs R. 2016. Quantification of glycine betaine, choline and trimethylamine N-oxide in seawater particulates: Minimisation of seawater associated ion suppression. Analytica Chimica Acta 938, 114-122.
  • 4. Fitzsimons MF, Probert I, Gaillard F, Rees AP. 2020. Dissolved organic phosphorus uptake by marine phytoplankton is enhanced by the presence of dissolved organic nitrogen. J. Exp. Mar. Biol. Ecol. 530-531, 151434.

Key Information

  • This project has been shortlisted for funding by the ARIES NERC DTP and will start on 1st October 2021. The closing date for applications is 23:59 on 12th January 2021.
  • Successful candidates who meet UKRI’s eligibility criteria will be awarded a NERC studentship, which covers fees, stipend (£15,285 p.a. for 2020-21) and research funding. For the first time in 2021/22 international applicants (EU and non-EU) will be eligible for fully-funded UKRI studentships. Please note ARIES funding does not cover visa costs (including immigration health surcharge) or other additional costs associated with relocation to 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. 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 in the subject area.
  • 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 significant relevant non-academic 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 click on the “Apply now” link below.

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