Dr Katherine Helliwell, Department of Biosciences, College of Life and Environmental Sciences, University of Exeter; Marine Biological Association
Professor Gáspár Jékely Department of Biosciences, Living Systems Institute, College of Life and Environmental Sciences, University of Exeter
Dr Adam Monier, Department of Biosciences, Living Systems Institute, College of Life and Environmental Sciences, University of Exeter
Professor Mike Allen, Department of Biosciences, College of Life and Environmental Sciences, University of Exeter; Plymouth Marine laboratory
Dr Glen Wheeler , Marine Biological Association
Location: University of Exeter, Streatham Campus, Exeter EX4 4QJ
This project is one of a number that are in competition for funding from the NERC GW4+ Doctoral Training Partnership (GW4+ DTP). The GW4+ DTP consists of the GW4 Alliance of research-intensive universities: the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus five unique and prestigious Research Organisation partners: British Antarctic Survey, British Geological Survey, Centre for Ecology & Hydrology, the Natural History Museum and Plymouth Marine Laboratory. The partnership aims to provide a broad training in the Earth, Environmental and Life sciences, designed to train tomorrow’s leaders in scientific research, business, technology and policy-making. For further details about the programme please seehttp://nercgw4plus.ac.uk/
For eligible successful applicants, the studentships comprises:
- An stipend for 3.5 years (currently £15,009 p.a. for 2019/20) in line with UK Research and Innovation rates
- Payment of university tuition fees;
- A research budget of £11,000 for an international conference, lab, field and research expenses;
- A training budget of £3,250 for specialist training courses and expenses.
- Travel and accommodation is covered for all compulsory DTP cohort events.
- No course fees for courses run by the DTP
We are currently advertising projects for a total of 10 studentships at the University of Exeter
Marine phytoplankton contribute almost half of global primary production, and represent a critical sink for rising atmospheric CO2. Biotic pressures such as grazing and viral infection are major sources of phytoplankton mortality, causing the termination of algal blooms, and shaping the structure of planktonic communities. Top-down biotic controls on phytoplankton productivity are thus critical drivers of global carbon fluxes in the ocean. To evade predation, phytoplankton can evoke a range of defense mechanisms: modifying cell size, shape or chain length, and/or producing harmful toxins to reduce palatability and predation encounter rates. These adaptive responses can have cascading impacts on food-web structure and ecosystem health. Despite this, mechanisms enabling important phytoplankton taxa to sense and respond to grazing, are largely unknown. The aim of this project is to employ an established state-of-the-art molecular tool-kit to examine the mechanisms controlling adaptive responses of phytoplankton to predators, and in turn determine the impact of such defenses on grazer behavior.
Project Aims and Methods
A major barrier to our understanding of phytoplankton-grazer interactions has been the lack of a fully genetically-tractable model system. This is essential to examine the genetic underpinnings of phytoplankton defence mechanisms, and their impact on grazer biology. This project will build on our established model algal species Phaeodactylum, with the annelid worm Platynereis that consumes Phaeodactylum in its early larval stages. This system offers a novel opportunity to study the basic molecular mechanisms governing phytoplankton-grazer interactions, and subsequently elucidate their broader impact on aquatic ecosystem functioning.
Determine the impact of Platynereis grazing on diatom cell physiology (growth, photosynthetic efficiency, morphology) and metabolism
Examine how diatom cells sense and respond to grazing pressure
Fluorescence microscopy with diatom strains expressing biosensors (e.g. to measure calcium) will enable real-time signalling responses to be visualised in response to grazer presence and/or diffusible cues.
Generation/examination of mutant lines via established CRISPR-Cas9 approaches will enable the molecular mechanisms underpinning such signalling responses to be elucidated.
3. Characterise the impact of diatom grazer defence mechanisms (e.g. toxin production) on predator behaviour (such as motility) and grazing rate
4. Examine the specificity and conservation of defence mechanisms underpinning diatom-grazer interactions:
The conservation of defensive mechanisms to different grazers (e.g. copepods, predatory protists), and between different ecologically-important diatom species will be examined.
NERC GW4+ funded studentship available for September 2020 entry. For eligible students, the studentship will provide funding of fees and a stipend which is currently £15,009 per annum for 2019-20.
References / Background reading list
 Amato et al., Grazer-induced transcriptomic and metabolomic response of the chain-forming diatom Skeletonema marinoi. The ISME Journal, 12: 1594–1604 (2018)
 Helliwell et al., Alternative Mechanisms for Fast Na+/Ca2+ Signalling in Eukaryotes via a Novel Class of Single-Domain Voltage-Gated Channels. Current Biology, 29, 1503–1511 (2019)
 Selander et al., Copepods drive large-scale trait-mediated effects in marine plankton. Science Advances. 5(2) (2019)