Journal: Nature Communications
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Deep reef refuges at risk
© Photography by Mangiwau/Getty
Deep reefs are not beyond the reach of coral bleaching due to warming seas.
Marine conservationists harbour hope that corals dwelling deep below the surface are safe from global warming.
A team that included researchers from the University of Queensland analysed sea temperatures on the Great Barrier Reef in Australia at depths between 5 and 100 metres. The data was recorded in 2016 when record-breaking surface temperatures bleached more than 60% of the region’s shallow coral (between 5 and 25 metres deep).
The team found that a seasonal current moving warm water to the surface initially kept deeper coral cooler. But once this current subsided, temperatures rose above the seasonal average, even at depth, bleaching 40% and killing 6% of coral 40 metres below the surface.
The depths provide some coral species a retreat from the summer heat, but prolonged periods of extreme warming could threaten the biodiversity of deep coral.
- Nature Communications 9, 3447 (2018). doi: 10.1038/s41467-018-05741-0