Shade as a protective measure during bleaching (C4.2)

Task leader: Prof Ove Hoegh-Guldberg, The University of Queensland

While the primary causal factor of coral bleaching is elevated water temperature, the mechanism involves damage to the ability of the algal symbionts to process light. Elevated water temperatures have the greatest effect on coral surfaces that are exposed to strong light. Potentially, shading small sections of coral reefs could be used to protect areas of regional or economic significance. In order to develop these technologies, it is envisaged that three phases of research be implemented.

Phase 1: Determining levels of shade needed to provide protection while not causing ecological changes as a consequence of reduced light (Experiments at Heron Island)

Phase 2: Field-testing of coral shade devices (CSD) Small shade devices will be constructed to create the shade conditions determined in Phase 1 will deployed on the Heron Island reef flat in December 2004. CSDs will use shade cloth (common at gardening supplies).

Phase 3: Field trails of CSDs at key tour operator sites

CSDs will be used to shade sections of coral reefs close to operator sites at Agincourt Reef. PAM technologies and bleaching detection protocols will be used to investigate the protection offered by shade – compared to unshaded control sites. Signs that the reef is changing due reduced light will be investigated closely. This will involve regular photographs and ecological analysis of the substrate changes.

An Honours student from the University of Queensland (Mr Eric Strom) is participating in the project full-time.