To truly understand the effects of climate change, in particular ocean acidification (OA), on marine fish we need to move away from measuring effects on single species and towards a more holistic understanding, both at the physiological as well as the molecular level.
Studies conducted on Atlantic cod have shown very complex responses (Stiasny et al., 2019). For cod OA is a ‘stealth stressor’, i.e. does not trigger a transcriptomic response (Mittermayer et al., 2019). This poses the question whether species, which appear to be more robust to OA (e.g. Atlantic herring (Sswat et al., 2018)) may be able to sense sense and react to OA on a molecular (i.e. transcriptomic) as well as a physiological level and whether these differences could help explain differential vulnerabilities to OA across species. This project is aiming to explore this possibility by conducting a comparative study exposing two species of temperate, marine fish, for which different vulnerabilities to ocean acidification are shown in the literature, to varying levels of ocean acidification. Identifying commonalities among species that are vulnerable or tolerant to OA will help to understand what it will take for fishes to survive in a future ocean.
This project will be based on experiments to explore the mechanisms underpinning OA responses during critical early life stages.
The project will seek to work with two species.
A dedicated literature review will be undertaken. Two species will be chosen based on previous knowledge in the literature on their vulnerability (geographically and physiologically). Fish will be exposed to OA and a control and maintained through as much of their life and reproductive cycles as possible. Experiments will be run at Cefas facilities in Weymouth and/or NOCS.
Home office licenses are in place and ethical approval will be sought before any work.
Besides the fundamental fitness proxies like survival and growth, we will measure metabolic rates, organosomatic indices, sperm mobility, ossification rates, and blood chemistry. Metabolic rates will be measured through oxygen consumption and using novel otolith isotope tools developed in Southampton. This will allow us to test whether OA responses incur a metabolic cost, or whether different metabolic phenotypes are more or less vulnerable to OA within a population.
Samples will be taken for transcriptomic analyses to see whether there is an epigenetic stress response. The species will be acclimatized prior to any experiment for a period of 10 days, which will provide sufficient time to study their feeding and behavioral activities.
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the School of Ocean and Earth Sciences. Specific training will include:
- Experimental ecology
- Fish larval rearing
- Ecophysiology and climate change ecology of marine fish
- Otolith reading and microchemistry
- Molecular biology (including lab work, i.e. DNA/RNA extractions)
- Data analysis and visualization (mainly in R)
- Presentation skills (oral and written)
- Scientific writing
- Participation and interaction with policy colleagues (e.g. Defra System Marine Climate Strategy and Coordination Group) via Silvana Birchenough at Cefas, to ensure the results are applied and could support decision-making in this new area.
Please see https://inspire-dtp.ac.uk/how-apply for details.
Mittermayer, F. H., Stiasny, M. H., Clemmesen, C., Bayer, T., Puvanendran, V., Chierici, M., Jentoft, S., & Reusch, T. B. H. (2019). Transcriptome profiling reveals exposure to predicted end-of-century ocean acidification as a stealth stressor for Atlantic cod larvae. Scientific Reports, 9(1), 1–11. https://doi.org/10.1038/s41598-019-52628-1
Sswat, M., Stiasny, M. H., Taucher, J., Algueró-Muñiz, M., Bach, L. T., Jutfelt, F., Riebesell, U., & Clemmesen, C. (2018). Food web changes under ocean acidification promote herring larvae survival. Nature Ecology and Evolution, 2(May), 1–5. https://doi.org/10.1038/s41559-018-0514-6
Stiasny, M. H., Sswat, M., Mittermayer, F. H., Falk-Petersen, I.-B., Schnell, N. K., Puvanendran, V., Mortensen, A., Reusch, T. B. H., & Clemmesen, C. (2019). Divergent responses of Atlantic cod to ocean acidification and food limitation. Global Change Biology, 25(3). https://doi.org/10.1111/gcb.14554