Sperm pHertility; are faster marine invertebrate sperm more susceptible to ocean acidification?

Dr Ceri Lewis, Prof Tamara Galloway, Prof Dave Hosken

Marine invertebrates adopt a vast array of reproductive strategies and demonstrate considerable variation in sperm morphology and physiology according to phylogeny, spawning habitat and fertilisation strategy. The combined influences of rising atmospheric CO2 and environmental pollution are now fundamentally altering the physicochemistry of the seawater into which these animals spawn at a rate exceeding anything in the historical and recent geological record.  Our research has demonstrated that ocean acidification (OA) and environmental contaminants disrupt sperm function by reducing sperm motility and respiration rates and inducing DNA damage for a number of broadcast spawning marine invertebrates. However strong species-specific differences in the level of response to these stressors have been observed, suggesting reproductive processes in some species will be more susceptible to environmental change than others.

The aim of this studentship is to investigate the role of sperm morphology and physiology in determining the level of environmentally induced sperm disruption as a result of ocean acidification and pollutant exposure. We aim to test the hypothesis that: ‘faster, shorter lived sperm are more susceptible to environmental disruption from ocean acidification and pollution than slower, longer lived sperm.’  You will conduct comparative studies of marine invertebrate sperm responses to CO2 induced ocean acidification (pH ranging from 8.1-7.4) and an environmental pollutant in terms of their viability, motility and longevity using computer assisted sperm analysis and live/dead fluorescent staining. Electron microscopy and antibody staining techniques (for proton pumps and calcium channels) will be employed to characterise sperm morphology and biochemistry for each species. A range of marine invertebrates (polychaetes, echinoderms and molluscs) covering different ‘spawning environments’ and phyla will be studied. In situ (field) and mesocosm experiments will look at how sperm traits influence fertilisation rates for different spawning environments.


You will be trained and supported by an enthusiastic team of Bioscience researchers providing you with a highly employable portfolio of skills in an area of key global importance. Experiments will be run at Streatham (Exeter) using the new state-of-the-art aquarium facilities with input on experimental design and interpretation from colleagues at Tremough (Cornwall).  There will be opportunities for wider travel during the project to collaborating partners across Europe. Applicants are required to have a good degree in a biological science and a strong interest in the marine environment.  For further details contact Dr Ceri Lewis at c.n.lewis@exeter.ac.uk Application details online at http://www.exeter.ac.uk/studying/funding/award/?id=923

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