PhD studentship: How do Organic Nutrients Sustain Shelf Seas Productivity?
Marine phytoplankton play vital roles in regulating the global climate, contributing almost half of net primary production. A major factor controlling phytoplankton assemblages is the availability of crucial nutrients including nitrogen (N) and phosphorus (P), the supply of which can vary dramatically in space and time. Most work examining the role of N and P in driving phytoplankton productivity has focused on inorganic forms (e.g., nitrate and phosphate). By comparison, the roles of organic N and P forms (DON and DOP, respectively), which can make up to 50% of the dissolved N and P pools in seawater, are poorly understood. We recently demonstrated that marine phytoplankton are capable of assimilating organic N and P, even in the presence of high levels of inorganic nutrients. Additionally, we have found that the availability of organic N forms enhances organic P acquisition, suggesting that phytoplankton coordinate N and P signalling and uptake pathways in order to maximise acquisition of these essential nutrients. The aim of this project is to integrate field and laboratory methodologies to further examine organic N and P usage and coordination by phytoplankton in the Western English Channel.
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The project will aim to characterise the dissolved organic nutrient pools in relation to the seasonal succession of coastal phytoplankton communities. The student will characterise compositional changes within the DON and DOP pools in the Western English Channel over the course of the annual cycle, coupling field sampling (on the PML research vessel Quest) with analytical chemistry using HPLC.
Physiological experiments with a range of phytoplankton will also be conducted to examine the bioavailability of environmentally relevant DON and DOP forms. Additionally, the nature (timescale, specificity and extent) of coordination between DON availability and DOP acquisition will be examined.
The successful candidate will gain training in a wide range of field and laboratory skills, including analytical chemistry (chromatography), phytoplankton physiology and marine biogeochemistry, and will have access to professional development opportunities.
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Second Supervisor (External Lead): Dr Katherine Helliwell
Lead Supervisor (DoS): Professor Mark Fitzsimons
Third Supervisor: Dr Andy Rees
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Applicants should have a first or upper second class honours degree in an appropriate subject or a relevant Masters qualification in physical or biological science with an analytical science component. The ideal candidate would be an enthusiastic, motivated individual interested in working at the intersect of field oceanography, analytical chemistry and microbiology.
Non-native English speakers must have an IELTS Academic score of 6.5 or above (with no less than 5.5 in any element) or equivalent.
The studentship is supported for 3.5 years and includes full Home tuition fees plus a stipend at the 2024/25 rate (to be confirmed; compare the 2023/24 rate of £18,110 per annum). The last 6 months of the four-year registration period is a self-funded ‘writing-up’ period. The studentship will only fully fund those applicants who are eligible for Home fees with relevant qualifications. Applicants normally required to cover International fees will have to cover the difference between the Home and the International tuition fee rates (approximately £12,697 per annum at 2023/24 rate).
If you wish to discuss this project further informally, please contact Dr Katherine Helliwell.
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For further information and to apply for this position please visit https://www.plymouth.ac.uk/student-life/your-studies/research-degrees/postgraduate-research-studentships and select the studentship you would like to apply for. Please clearly state the name of the studentship that you are applying for on your personal statement.
For a list of supporting documents to upload with your application or more information on the admissions process generally, please visit our How to Apply for a Research Degree webpage or contact the Doctoral College.