Oxygen dynamics and their biological effects in Cardiff Bay

Cardiff University

About the Project

Cardiff Bay is an artificial 200 ha lake formed in 2001 by the impoundment of the Rivers Taff and Ely at their confluence with the Severn estuary. The lake is a focus for urban development and is important to amenity, recreation and culture. Cardiff Bay also functions as a locally important ecosystem, in particular as an important migratory route for Atlantic Salmon Salmo salar en route to spawning habitats in the Taff. Dominantly for this reason, there is a specific legal requirement under the Cardiff Bay Barrage Act (1993) to maintain dissolved oxygen concentrations in the Bay at > 5 mg/L throughout the year. Cardiff Harbour Authority (CHA) deliver this need using a bay-wide aeration system. While there is a clear biological need to maintain oxygen levels, there is now an opportunity to re-examine the present operating regime in the light of i) financial costs; ii) carbon costs; iii) reduced BOD and improving water quality in the Taff and Ely; iv) risks of increasing summer temperatures and v) oxygen dynamics in the Bay linked to planktivory and oxygen uptake by a large population on non-native bivalves.

The project will support two fully-funded PhD students supervised by a team combining the strengths of Cardiff University’s Schools of Biosciences and Earth/Environmental Sciences alongside Cardiff Harbour Authority. In outline, the work will involve i) the analysis of existing physico-chemical data from the Bay, ii) unique whole-lake experiments to vary the existing oxygenation regime and iii) novel assessments of biological responses to varying oxygen concentrations using biochemical markers in sentinel organisms (eg zebra mussles, algae or zooplankton).

The respective applicants should ideally have some combination of the following skills and interests:

1)     PhD in oxygen dynamics

This PhD will focus on analysing the oxygen dynamics and other physico-chemical variations in Cardiff Bay through time and space. You should have a first degree or Masters’ degree with interests and knowledge of limnology and algology, physico-chemical dynamics in lake systems, data analytical skills to work with large environmental data sets, and insights into field experimentation ideally with field experience.


2)     PhD in biological markers of deoxygenation and oxygen dynamics in aquatic organisms

This PhD will focus on the biological effects of variations in oxygen concentrations using lipidomic indicators of deoxygenation effects and ecosystem dynamics through the use of long-chain fatty acids, lipid unsaturation and glycerolipids in algae (Holm et al. 2022; Science, 376, 1487-1491) and/or benthic organisms such as Zebra Mussels. You should have a first degree in environmentally oriented biology and biochemistry with some combination of laboratory skills and, ideally, experience of working in field environments.

The studentships will commence in October 2023 and will cover tuition fees (at UK level) as well as a maintenance grant. In 2022-23 the maintenance grant for full-time students was £17,668 per annum. As well as tuition fees and a maintenance grant, the students will have access to courses offered by the University’s Doctoral Academy and become members of the University Doctoral Academy.

As we expect a very high standard of applications, the successful applicant is likely to need a very good first degree (a First or Upper Second class BSc Honours or equivalent) ideally with Masters’ level experience and/or relevant research experience.

How to apply:

You can apply online – consideration is automatic on applying for a PhD in Biosciences, with an October 2023 start date.

Please use our online application service at


and specify in the funding section state the name of the funder/that you wish to be considered for Cardiff Harbour Authority funding.

Please specify that you are applying for this particular project and the supervisor.

Information on the application process can be found here


Application deadline: 3rd July with interviews (either in person or by Skype) being held on the week commencing 10th July


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