Understanding environmental controls and predicting climate change effects on the health and occurrence of coral communities and their constituent organisms

Guinotte, John Michael (2006) Understanding environmental controls and predicting climate change effects on the health and occurrence of coral communities and their constituent organisms. PhD thesis, James Cook University.

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Abstract

Research presented in this thesis provides insight into important environmental controls on coral occurrence and survival, potential climate related problems coral ecosystems face in the coming decades, the probable temporal and spatial progression of these problems, and provides tools that will aid the science community in anticipating range shifts and in identifying areas for protection. These topics are addressed by investigating four research foci, which follow a logical progression from shallow-hermatypic, to deep-hermatypic, to deep-ahermatypic corals. This is due largely to the success of early model predictions for shallow-hermatypic corals and the fact that new applications of the methodologies were quickly recognized for deep-hermatypic and ahermatypic coral ecosystems. The latter two are breaking novel ground and opening new fields of study. Model results indicate both hermatypic and ahermatypic coral ecosystems, which are presently under intense anthropogenic stress, will face even greater challenges within the century. Research findings presented in this thesis show the primary drivers behind the 1998 coral bleaching event on the Great Barrier Reef were a combination of low winds, clear skies, and neap tides. These conditions caused sea surface temperatures to rise and resulted in significant coral mortality. Coral bleaching events have persisted post 1998 and will continue to occur in the future. Model projections indicate that rising atmospheric CO2 concentrations will significantly reduce the saturation state of carbonate minerals in the surface ocean and the deep sea within the century. By 2070, nearly all reefs in the Pacific basin will be “marginal” with respect to aragonite, which will probably result in long-term, gradual decreases in calcification, reef accumulation, and changes in community structure. The projections indicate this “saturation stress” will be compounded by rising average sea surface temperatures throughout much of the Pacific, including the Indo-Pacific center of coral diversity. Decreases in aragonite saturation state will not be limited to the surface ocean and will probably have negative affects on the calcification rates/mechanisms of deep sea scleractinian bioherms and marine plankton throughout the world's oceans. Modeling suitable reef habitat from environmental data successfully predicted numerous uncharted deep-hermatypic reefs within the Great Barrier Reef Marine Park and Timor Sea. Identifying the location of deep-hermatypic reefs will become increasingly important in the coming decades as these areas are less likely to experience coral bleaching events. Light availability and average nitrate were the most important variables in determining where reefs (both modeled and documented) occur. Temperature, salinity, and phosphate concentration were also statistically significant. An online spatial analysis tool was developed to predict potential ranges of marine organisms (e.g. sea anemones and anemonefishes) and areas which could be susceptible to marine species invasions. These predictions were derived by examining the environmental characteristics of waters surrounding known locations of constituent reef organisms. Documented locations of anemonefishes and their sea anemone hosts were used as a case study, but this tool is applicable for all marine taxa that live within relatively well defined environmental limits. A promising future application of this tool is to predict species range shifts due to climate change.

Item ID: 24947
Item Type: Thesis (PhD)
Keywords: coral reefs; marine fauna; climate change; diagnostic models; coral bleaching; Great Barrier Reef; habitats; sea surface; temperature; carbon dioxide; aragonite saturation; calcification; light availability; nutrients; nitrate; phosphate; deep-sea corals; anemone fishes; sea anemones; seawater chemistry; spatial analysis; Pacific Basin; Timor Sea
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Publications arising from this thesis are available from the Related URLs field. The publications are:

Guinotte, J., and Skirving, W. (2001) The sea surface temperature story on the Great Barrier Reef during the coral bleaching event of 1998. In: Oceanographic processes of coral reefs: physical and biological links in the Great Barrier Reef. CRC Press, Boca Raton, FL, USA, pp. 301-313.

Guinotte, J.M., Buddemeier, R.W., and Kleypas, J.S. (2003) Future coral reef habitat marginality: temporal and spatial effects of climate change in the Pacific basin. Coral Reefs, 22 (4). pp. 551-558.

Guinotte, J.M., Bartley, J.D., Iqbal, A., Fautin, D.G., and Buddemeier, R.W. (2006) Modeling habitat distribution from organism occurrences and environmental data: case study using anemonefishes and their sea anemone hosts. Marine Ecology Progress Series, 316 . pp. 269-283.

Guinotte, John M., Orr, James, Cairns, Stephen, Freiwald, Andre, Morgan, Lance, and George, Robert (2006) Will human-induced changes in seawater chemistry alter the distribution of deep-sea scleractinian corals? Frontiers in Ecology and the Environment, 4 (3). pp. 141-146.

Date Deposited: 12 Feb 2013 00:06
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 50%
96 ENVIRONMENT > 9603 Climate and Climate Change > 960399 Climate and Climate Change not elsewhere classified @ 50%
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