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Jon Havenhand

Research Interests

  • Ocean Acidification: impacts on fertilisation, developmental ecology, and settlement success of marine invertebrate larvae
  • Reproductive ecology and evolution of larvae

Ocean Acidification: Rising levels of carbon dioxide in the atmosphere are making the oceans more acidic.  In the last 150 years, fossil fuel burning has caused the pH of the oceans to fall by 0.1 units – a seemingly small change, but one that is equivalent to a 30% increase in acidity.  By the year 2100 it is reliably estimated that oceanic pH will be ~ 0.5 units lower than at present (equivalent to a 3x increase in acidity).  The impacts of this change have barely begun to be understood, however it is clear that many species will have extreme difficulty in forming the calcareous skeletons and shells that are essental for their survival. Alarmingly, almost no studies have investigated the effects of this increasing acidity on coastal marine ecosystems, and the few data that do exist suggest that delicate early life-history stages such as fertilisation and larval development may be particularly susceptible.  This project, in collaboration with Prof. Mike Thorndyke, and Dr Sam Dupont, at Kristineberg Marine Research Station, Sweden, assesses the impacts of ≤ 0.5 pH unit decreases in ocean pH on within-species variation in early life-history characters of key ecosystem-structuring species of marine invertebrate. The results are providing the first estimates of the likely capacity of marine species to adapt to the coming changes in ocean acidity, and will facilitate the parameterisation of predictive models regarding the impacts of ocean acidification on the resilience, dynamics and integrity of Swedish coastal ecosystems.  This will, in turn, inform future strategies for the management and conservation of our marine environment, and the ecosystem services it provides.

Reproductive Ecology: My previous research has shown that fertilisation success, larval swimming behaviour and larval survivorship are all strongly influenced by parentage. The effects of parentage on fertilization success and larval behaviour are only beginning to be understood in marine ecology and have widespread implications for our understanding of natural spawning processes, fertilisation "strategies" and (hence) the susceptibility of wild populations to disturbance and/or exploitation. This work is partly published (Kupriyanova & Havenhand 2002, 2005) and partly in preparation for publication.

More recent research has focussed on two collaborative projects:

Parental variation in fertilization success: this project, with Dr Craig Styan, Deakin University, Australia, has shown that parentage can strongly influence the likelihood that gametes will interact positively. This work extends that of other recent authors to show that likelihood of sperm activation, and hence fertilization, in response to female gametes can vary markedly between males within a population.

Fertilization ecology of sea urchins: this project, with Dr Jane Williamson, Macquarie University, Australia, is investigating the impacts of sperm concentration and parentage on fertilisation success in Australian sea urchins. Results to date suggest that sperm concentrations that yield high fertilisation success may not yield correspondingly high larval survivorship. Results are in preparation for publication.

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