Autonomous insights into algal nutrient uptake


Around half of global primary production occurs in the marine realm through the activity of microscopic algae (termed phytoplankton), who support highly productive ecosystems and drive biogeochemical cycles. Algal growth requires essential elements (C, N, P, Si, Fe), although the recipe (or stoichiometry) in which these nutrient elements are used varies between different taxa, alongside some level of environmental plasticity. Deviations in the availability of these nutrients directly influence algal ecology and physiology, with compounding effects up the food chain and across biogeochemical cycles. Our understanding of this elemental uptake is limited as we rely on low-resolution sampling, whilst cellular processes occur at far shorter time and space scales. Autonomous sensor technology represents a unique breakthrough that can overcome these limitations, allowing us to monitor nutrient uptake and cellular processes at metabolically relevant scales. This project will utilize autonomous nutrient sensors to understand sub-hourly variability in stoichiometry in the context of algal biochemical composition and metabolic processes. Such an understanding of algal stoichiometry has several wider implications, for example in understanding the coupling of biogeochemical cycles, interpreting high-resolution autonomous biogeochemical field measurements, or closely monitoring algal growth in industrial and economically critical situations (e.g. biofuel production, waste water remediation, aquaculture).

The project will apply autonomous nutrient sensors in an algal growth unit, allowing monitoring of nutrient uptake, biochemical composition and metabolic processes at short temporal-scales (< 1h). Nutrient measurements at these scales will be compared with simultaneous determination of biochemical composition under simulated laboratory-controlled environmental variability (e.g., day-night cycles). Application of the insights gained into natural communities could include freshwater and estuarine lochs (Loch Leven), coastal upwelling sites (Agulhas Bank), or a tropical shelf-sea (Singapore Strait). The student will be hosted at Heriot-Watt University, within the Lyell Centre, utilizing state-of-the-art climate-controlled seawater aquarium and novel geochemical analytical facilities. Nutrient sensing will use cutting-edge autonomous sensors from the National Oceanography Centre, Southampton that have been developed at the NOC-S, and deployed in a variety of aquatic environments (rivers, estuaries, open-ocean). The sensors rely on microfluidics to provide rapid, calibrated measurements on small sample volumes, enabling collection of higher-frequency nutrient concentration data than is practical with conventional methods. The student will spend around 3-months at the NOC over the course of the first 18-months of the project, where they will receive specialist training in this technology. This project will contribute directly to the Lyell Centre’s remit to undertaken novel and transformative multidisciplinary research.

The NEXUSS CDT provides state-of-the-art, highly experiential training in the application and development of cutting-edge Smart and Autonomous Observing Systems for the environmental sciences, alongside comprehensive personal and professional development. There will be extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial / government / policy partners. The student will be registered at Heriot-Watt University, and hosted at the Lyell Centre for Earth and Marine Science and Technology.

Specific training includes: Microfluidic sensors for nutrient determination (nitrate, phosphate, silicic acid); Traditional techniques for nutrient determination; Algal cultivation, ecology, physiology and taxonomy; Biochemical analysis of major element and macromolecular composition; Physiological rate measurements (e.g. growth rate, photosynthesis, respiration); Univariate and multivariate statistical techniques.

Further Reading

Arrigo (2005). Marine microorganisms and global nutrient cycles, Nature 437, doi: 10.1038/nature04158.

Moore et al. (2013). Processes and patterns of oceanic nutrient limitation. Nature Geoscience 6, doi: 10.1038/ngeo1765.

Grand et al. (2017). A lab-on-chip phosphate analyzer for long-term In Situ monitoring at fixed observatories: Optimization and performance in estuarine and oligotrophic coastal waters. Frontiers in Marine Science 4, doi: 10.3389/fmars.2017.00255.


This project has been shortlisted for funding via the Next Generation Unmanned Systems Science (NEXUSS) Centre for Doctoral Training, funded by the Natural & Environmental Research Council (NERC) and the Engineering & Physical Sciences Research Council (EPSRC). The scholarship will cover tuition fees and provide an annual stipend of approximately £14,500.


To be eligible, applicants must meet the RCUK’s eligibility criteria. Applicants should have a first-class honours degree or a 2.1 honours degree plus Masters (or equivalent) in a relevant subject (e.g., Earth or Environmental Science, Biology, Oceanography, Marine Science or Chemistry). Scholarships awarded by competitive merit, taking into account the academic ability of the applicant.

How to Apply

Please complete our online application form.

Please select PhD programme Marine Biology and include the full project title, reference number and supervisor on your application form. You will also need to provide a CV, a supporting statement, a copy of your degree certificate and relevant transcripts and references from two academic sources.

Informal project-related enquiries addressed to Alex Poulton at


The deadline for applications is 5th January 2018. The successful applicant would be expected to start in October 2018.

posted: 14 November 2017     Please mention EARTHWORKS when responding to this advertisement.