Essential fatty acids in the trophic ecology of an invasive lake bivalve
Applicants (UK, EU and international) capable of self-funding or with scholarship are welcome to apply.
Primary Supervisor: Dr Irina Guschina
Secondary Supervisors: Prof John Harwood & Prof Steve Ormerod
Shortly after completion in 2001, Cardiff Bay was invaded by the non-native zebra mussel Dreissena polymorpha. Unchecked by natural enemies, by 2009 this bivalve had covered hard surfaces throughout the Bay at densities of 1-6,500 m-2, reaching a total population of 10-31 million adults. While several major ecological effects are likely, a major concern is that zebra mussels will reduce the Bay’s oxygen concentrations by respiratory uptake and by depleting oxygen-producing phytoplankton. Consequences for other lake organisms, and for the legal requirement to maintain oxygen concentrations above 5 mg/L, would be catastrophic in this £220 million amenity.
In the absence of options for eliminating zebra mussels, there is an urgent need to understand factors that limit their numbers. One hypothesis is that zebra mussels will become self-limiting through their own depletion of algal production and the loss of associated key resources, notably essential fatty acids.
Evidence shows that algae affect the growth and development of bivalves by supplying C18 polyunsaturated fatty acids (PUFAs) which they cannot synthesise. Bivalves also have limited capacity to form the long-chain PUFAs (i.e. with >C18) that are important in development, survival and population growth. While we have extensive data on zebra mussels in Cardiff Bay, alongside preliminary data on seasonal variability in the fatty-acid profiles of algae and mussels, links between algal supply, fatty acid availability and mussel dietary requirements are poorly known.
The student will test the above hypothesis through field sampling and field/laboratory experiments to establish factors affecting algal use and trophic limits in zebra mussels. In addition to revealing factors affecting the distribution of this species, the results will allow improved prediction of how population dynamics and distribution will be affected by algal quality.
The results will have wider application to factors affecting this major invasive species throughout its range.