Thesis: Tolerance and ‘Tipping Points’ to Environmental Stressors in Reef- Building Corals: Evaluating through Mesocosm Experiments and Geochemical Analysis
Corals are living organisms that lay down calcium carbonate based structures as they make their calcium carbonate skeleton trace elements and isotopes of different elements found in the environmental seawater are also incorporated into this lattice structure. Through the development of geochemical techniques we are able to measure the ratio and concentration of these elements which can tell us much about the environment the coral has grown in. My research looks into further developing our understanding of these environmental indicators using geochemical techniques and defining if our interpretation of these indicators is correct against the processes of calcification.
Coral reefs are thought of as being sensitive to environmental change. It is generally accepted that corals will increasingly find it difficult to remain ecologically sustainable habitats as sea surface temperatures rise and the pH of the ocean lowers, largely due to the increased amount of atmospheric CO2. Some regions of reefs may be more susceptible then others. The resilience and tolerance of reefs to environmental change may be due to their past experience of thermal exposure. Corals living in extreme environments, such as those from Cygnet Bay in Western Australia, maybe more resistant to further thermal extremes, however they may be nearer their thermal ‘tipping point’ and be already be living at less than optimal conditions for growth and reproduction. My research hopes to elucidate some of these issues and help our understanding of coral growth and survival in a high CO2 world.
Why my research is important
Atmospheric carbon dioxide has already risen substantially since pre-industrial times this has already had consequences for the world climate including raising average sea surface temperatures and reducing the pH of the oceans. Corals reefs are important ecosystems for fisheries, biodiversity and form natural coastal defence systems. It is important to understand how these systems will react to the environmental changes they will face in the future.