Isabel Jimenez-Denness

Heat Transfer in Corals and Implications for Coral Bleaching


Isabel Jimenez-Denness Current Appointment: PhD Candidate Contact: Institute for Water and Environmental Resource Management Department of Environmental Sciences Aquatic Photosynthesis Group University of Technology, Sydney PO Box 123 Broadway NSW 2007 Australia Office: Building 4, Level 5, Room 66 (City Campus) Phone: 9514 8345 Fax: 9514 4079 Email: Isabel.Jimenez@student.uts.edu.au Project Outline This project investigates the thermal processes that govern a coral’s heat budget and how this affects its temperature. This will allow a better understanding of the transfer of heat between a coral and its surroundings and predict physical conditions responsible for coral bleaching. During a bleaching event, corals lose their symbiotic dinoflagellate algae, known as zooxanthellae. This makes the underlying calcium carbonate skeleton visible below the living tissue and results in the vivid white colour of bleached corals. More often than not it also leads to the death of the coral host, which relies on the symbiotic micro-algae for survival. Abnormally high sea surface temperatures (1-2 ºC above mean seasonal maximum, associated with global climate change) and intense light have been identified as major factors causing widespread and devastating bleaching events, which are becoming increasingly frequent around the world. On large geographical scales it is possible to detect abnormally high sea surface temperatures and thus identify bleaching “hot spots”, or regions of the world’s tropical oceans that are at risk. However at the scale of a coral reef it is much more difficult to predict the onset or even the severity of a bleaching event. Individual coral colonies don’t bleach at the same time or with the same intensity. To address this still poorly understood aspect of bleaching, this project focuses on the temperature of the calcium carbonate skeleton, at the scale of individual colonies, and investigates the response to environmental factors such as surrounding water temperature, flow, and solar radiation. Supervisors Associate Professor Peter Ralph Professor Greg Skilbeck

Isabel Jimenez-Denness

Project Outline

Supervisors