Publications (5)3.88 Total impact
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Article: Sea-surface temperature and thermal stress in the Coral Triangle over the past two decades
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ABSTRACT: Increasing ocean temperature has become one of the major concerns in recent times with reports of various related ecological impacts becoming commonplace. One of the more notable is the increased frequency of mass coral bleaching worldwide. This study focuses on the Coral Triangle region and utilizes the National Oceanic and Atmospheric Administration-Coral Reef Watch (NOAA-CRW) satellite-derived sea surface temperature (SST) and Degree Heating Weeks (DHW) products to investigate changes in the thermal regime of the Coral Triangle waters between 1985 and 2006. Results show an upward trend in SST during this period with an average rate of 0.2°C/decade. However, warming within this region is not uniform, and the waters of the northern and eastern parts of the Coral Triangle are warming fastest. Areas in the eastern part have experienced more thermal stress events, and these stress events appear to be more likely during a La Niña.Coral Reefs 04/2012; 28(4):841-850. · 3.88 Impact Factor -
Chapter: Climate Variability and Change: Monitoring Data and Evidence for Increased Coral Bleaching Stress
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ABSTRACT: Coral reefs live within a fairly narrow envelope of environmental conditions constrained by water temperatures, light, salinity, nutrients, bathymetry and the aragonite saturation state of seawater. While the natural environment can be highly variable and potentially stressful to corals, humans are now placing the world’s coral reefs in crisis as a result of direct local- to regional-scale insults combined with accelerating global changes. The global-scale insults result from increased concentrations of atmospheric greenhouse gases that are rapidly acidifying and warming ocean waters. This chapter focuses on the changing physical environment surrounding coral reef ecosystems and especially the rising SSTs that are responsible for most mass coral bleaching events. We make use of improved long-term records of surface ocean climate to document SST changes in the vicinity of coral reefs and how the risk of SST conditions conducive to coral bleaching varies with climate variability such as El Niño--Southern Oscillation events. We describe the application of satellite-based SSTs and related products that have been developed to detect and monitor environmental conditions leading to coral bleaching around the globe.10/2008: pages 41-67; -
Conference Proceeding: HF Ocean Surface Radar Monitoring for Coral Bleaching in the Great Barrier Reef
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ABSTRACT: HF ocean surface radar provides a valuable multi-parameter monitoring technique for the investigation and management of coral bleaching. The physical parameters normally associated with bleaching are temperature and light, which are primarily controlled by insolation, wind, waves and currents. The radar provides a useful monitoring of wind and waves, and is the leading technology for monitoring surface currents. The deployment of an HF radar in the Great Barrier Reef at the Heron Island study area provides ideal infrastructure for the study of the physical processes which affect coral bleaching and the spread of coral diseaseOCEANS 2006; 10/2006 -
Article: Early cellular changes are indicators of pre-bleaching thermal stress in the coral host
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Article: Early cellular changes are indicators of pre-bleaching thermal stress in the coral host
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ABSTRACT: Thermal stress causes the coral-dinoflagellate symbiosis to disassociate and the coral tissues to whiten. The onset and occurrence of this coral bleaching is primarily defined via the dinoflagellate responses. Here we demonstrate that thermal stress responses occur in the coral host tissues in the days before the onset of coral bleaching. The observed sequence of thermal responses includes reductions in thickness of coral tissue layers and apoptosis of the cells prior to reductions in symbiont density. In the days before the onset of coral bleaching the outer coral tissue layer (epithelium) thickness reduces and apoptosis occurs within the gastrodermis. Two days following this, coinciding with an initial reduction of symbiont density (by approximately 25%), gastrodermal thickness decreased and apoptosis of host cells was identified in the epithelium. This was eventually followed by large reduction in symbiont density (by approximately 50%) consistent with coral bleaching. Both pro-apoptotic and anti-apoptotic genes are identified in the reef building coral Acropora aspera, demonstrating the necessary pathways are present for fine control of host apoptosis. Our study shows that defining periods of host stress based on the responses defined by dinoflagellate symbiont underestimates the importance of early cellular events and the cellular complexity of coral host.Journal of Experimental Marine Biology and Ecology.
