Killer hotspots of over-heated ocean water which destroy huge areas of coral and bring starvation to birds, fish and other sea creatures can now be pinpointed, thanks to a major advance in the use of satellite technology by Australian and American researchers.
Advanced satellites and smart mathematics are enabling the scientists to detect the events which cause mass bleaching of corals and disruption of marine food chains with unprecedented precision.
This is revealing the Great Barrier Reef’s most threatened areas under global warming.
“Until now we have only been able to detect large-scale events under typical seasonal conditions,” team leader and University of Queensland researcher Dr Scarla Weeks said.
“The new technology gives us the power to see what is happening in the ocean around the Great Barrier Reef in much finer scale in both space and time,” said Dr Scarla Weeks, of UQ’s Centre for Marine Studies (CMS) and Centre for Remote Sensing and Spatial Information Science (CRSSIS).
“It means we can identify those areas most at risk of being hit by hot water, enabling managers and reef visitors to take greater steps to protect them.
“It also means that we can observe coral bleaching events taking place, which were missedbefore because the satellite data didn’t have the fine scales necessary.”
Dr Weeks said that the 2002 bleaching event, which hit 54 per cent of the Great Barrier Reef was clearly detected using satellite data from the US National Oceans and Atmosphere Administration (NOAA) – but the subsequent 2005/6 event, which hit the southern GBR hard, was not picked up.
“One reason was the 2005/6 bleaching was an anomaly. It struck in November/December, whereas the usual time that warm water enters the GBR is in late summer, around February.
“The existing technology used didn’t have the resolution to pick it up. In fact it couldn’t observe any reefs close inshore.”
Dr Weeks’ team has announced the development of a satellite and mathematical tool that provides a dramatic improvement in the ability to read sea surface temperature anomalies from outer space. It is more accurate in time and can see much smaller areas of water.
“Using this we can identify individual reefs or groups of reefs which are most at risk of hot water and coral bleaching under climate change,” she said.