An investigation into the ability of bleached corals to cope with dredging related stressors has found that several species of thermally bleached corals cannot clear sediment that has smothered them, said Western Australian Marine Science Institution (WAMSI).
The study was undertaken as part of the WAMSI’s Dredging Science Node at the AIMS National Sea Simulator in specially developed tank systems.
Corals were subjected to elevated temperatures to cause bleaching and then exposed to various rates of sediment deposition, or smothering. Bleached corals were found to be able to remove about three times less sediment than those that were not bleached, WAMSI said.
“Lead researcher Pia Bessell-Browne from The University of Western Australia Oceans Institute, Center for Microscopy, Characterization and Analysis and Australian Institute of Marine Science, said that as coral bleaching events become more common we need to increase our understanding of how these large scale pressures interact with more local pressures, such as dredging activities,” according to the WAMSI’s announcement.
“This has important implications for management, as it demonstrates that precautions should be put in place to reduce the impact of dredging related pressures, and in particular sediment deposition, during periods of elevated ocean temperatures that could result in coral bleaching,” Ms Bessell-Browne said.
The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside Energy, Chevron Australia and BHP Billiton as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment.