student profile: Mr Mitch Gibbs


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Thesis work

Thesis title: To determine the impact of climate change on the energy reserves of oyster larvae and whether larvae from oysters of transgenerational exposure to elevated CO2 positively affects larval energetics

Supervisors: Maria BYRNE , Pauline ROSS , Laura PARKER

Thesis abstract:

Parental effects passed from adults to their offspring have been identified as a source of rapid acclimation that may allow marine organisms to persist as surface ocean continues to decrease in pH and increase in temperature. Little is known as to whether parental effects are beneficial for the next generation under multiple stressors and if these parental effects change the “point of no return” (PNR) for the organism. To increase our understanding of mechanisms that support tolerance to these stressors, the lipid compositions were explored with a range of sensitivities to climate change, experimentally exposed to ocean warming, ocean acidification and a combination, in accordance to the predictions of 2100. The adult organisms were exposed to stressors of CO2 (control 340: 856 µatm) and temperature (control 24oC; 28oC). The progeny of these organisms were put into a feeding delay experiment with the stressors of climate change. The feeding delay illustrates the extent of the organism’s ability to survive on their endogenous reserves of energy and the impacts of the stressors. A combination of the morphological and biochemical data illustrates a deeper understanding of the transgenerational effects and how this effects the PNR of the organism.

Anthropogenic modifications to the marine environments are widespread and increasing. As this continues it is unclear the full effects this has on the local fauna and their progeny. It is important to understand how the next generation will be affected by these changes (temperature, pH and food availability), and if these induce a transgeneration effect (maternal investment to the next generation). The transgenerational effect will be measured by the amount of lipid (energy) the egg or larvae possess. With changing conditions, the environment will become much more stressful, and it is likely that the algae blooming events will become later suggesting that larvae will have to survive a longer period without food and feed off their endogenous reserves. In this thesis I start by effecting parents by a change in pH and temperature. Then, I spawn them and affect the next generation with a feeding delay experiment ascertaining a “point of no return” (PNR). The PNR can identify the maximum period of time an organism can survive without food, and once the organism has been given food can it continue to survive. How will the extra stress of temperature and pH affect their PNR and will their PNR differ due to their parents. Their amount of lipid contents (energetic reserves) and morphological data will be used to answer these.

Selected publications

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Journals

  • Parker, L., O'Connor, W., Byrne, M., Dove, M., Coleman, R., Portner, H., Scanes, E., Virtue, P., Gibbs, M., Ross, P. (2018). Ocean acidification but not warming alters sex determination in the Sydney rock oyster, Saccostrea glomerata. Proceedings of the Royal Society B: Biological Sciences, 285(1872), 1-9. [More Information]
  • Parker, L., O�Connor, W., Byrne, M., Coleman, R., Virtue, P., Dove, M., Gibbs, M., Spohr, L., Scanes, E., Ross, P. (2017). Adult exposure to ocean acidification is maladaptive for larvae of the Sydney rock oyster Saccostrea glomerata in the presence of multiple stressors. Biology Letters, 13(2), 1-5. [More Information]

2018

  • Parker, L., O'Connor, W., Byrne, M., Dove, M., Coleman, R., Portner, H., Scanes, E., Virtue, P., Gibbs, M., Ross, P. (2018). Ocean acidification but not warming alters sex determination in the Sydney rock oyster, Saccostrea glomerata. Proceedings of the Royal Society B: Biological Sciences, 285(1872), 1-9. [More Information]

2017

  • Parker, L., O�Connor, W., Byrne, M., Coleman, R., Virtue, P., Dove, M., Gibbs, M., Spohr, L., Scanes, E., Ross, P. (2017). Adult exposure to ocean acidification is maladaptive for larvae of the Sydney rock oyster Saccostrea glomerata in the presence of multiple stressors. Biology Letters, 13(2), 1-5. [More Information]

Note: This profile is for a student at the University of Sydney. Views presented here are not necessarily those of the University.