Using biomineralisation responses to predict molluscan species-specific pathways for resilience to climate change. (What is the molluscan species-specific biomineralisation response to ocean acidification and how does this compare between adults and juveniles?)

This fully funded, 42-month PhD project is part of the SUPER DTP. The SUPER DTP is built around a well-established collaborative group of universities delivering world-leading research in natural environmental science.

This exciting PhD asks how does the molluscan biomineralisation response to climate change compare between adults and juveniles. Warming and acidification have been observed at a rate of 0.2 °C and 0.09 pH units per year in recent studies of coastal estuaries of NE Pacific (Lowe et al., 2019) and Australia (Scanes et al., 2020), an order of magnitude faster than any predicted ocean model. The mechanisms of ocean and coastal acidification differ (Fitzer et al., 2019a), however similarities occur in respect to the increases in dissolved inorganic carbon and reduced availability of carbonate for calcium carbonate shell production (Fitzer et al., 2019a), problematic for mollusc biomineralisation (Byrne and Fitzer, 2019). Mollusc shells are comprised of calcium carbonate mainly in two forms or polymorphs either aragonite, calcite or a composite of both. Calcite is less susceptible to dissolution at lower pH values than aragonite, so it is thought that aragonite producing species may be more vulnerable to future ocean acidification. Recent experimental research suggests that mechanisms of carbon uptake or biomineralisation pathways differ between molluscan species, however similarities occur related to the shell polymorph of calcium carbon, aragonite and calcite (Mele et al., 2023; Lee et al., 2021). Larval life stages are thought to be more vulnerable to ocean acidification and yet many studies examining the impact on shell growth have focused on adult stages (Meng et al., 2018). In molluscs grown under ocean acidification, low pH has been shown to reduce shell thickness, hardness and fracture toughness in mussels and oysters (Mele et al., 2023), problematic for shell protection against predators. This project will examine the effects of ocean acidification and naturally occurring coastal acidification on mollusc shell strength in adults and juveniles of two species of commercially cultured molluscs, the mussel, Mytilus sp. and oyster Magallana gigas. 

Impactful outcomes:

This project will make advances to identify species specific or polymorph specific biomineralisation response to identify molluscs potentially more resilient to ocean acidification, relevant to conservation of molluscan species including restoration of native oyster and to molluscan aquaculture communities.

To achieve this three core work packages will be explored; 1) Shell polymorph and species-specific biomineralisation response (shell hardness, fracture toughness and therefore the protective function of the shell) to ocean acidification and how does this compare between adults and juveniles and 2) species specific biomineralisation response to coastal acidification (low salinity gradients, low pH, and low total alkalinity environments) and 3) How do changes in biomineralisation response to environmental acidification relate to gene expression (applying (transciptomics) in molluscs.

Informal enquiries encouraged, please contact Dr Susan Fitzer, [Email Address Removed] for further information.

Applications should be made via the University of Stirling's PhD application webpage for Aquaculture: Course Application - University of Stirling

Please do not apply via findaphd.com.

If you require any additional assistance in submitting your application or have any queries about the application process, please don't hesitate to contact the Postgraduate Admissions team [Email Address Removed]

SUPER DTP Application web page: https://superdtp.st-andrews.ac.uk/how-to-apply/