Under pressure; deeper parts of the Great Barrier Reef impacted by climate change

What is it about?

Climate model projections of coral reefs have solely been made using surface temperatures and failed to consider vast areas of deeper ‘mesophotic’ reefs at 30 to 50 m. We identify areas of the Great Barrier Reef where separation of warm surface seawater from cooler deeper seawater insulates deeper reefs from surface warming. These areas have the potential to act as deep-water refuges from surface heatwaves. Refugia should help protect mesophotic species, even though many shallow species are not found in deeper areas. However, the protection offered by this ‘insulation’ is unlikely to last much more than a couple of decades. Worse, if society does not take the drastic action required to keep global warming below 2 °C, we find that warming is likely to pass critical thresholds even at mesophotic depths.

Featured Image

Photo by Yanguang Lan on Unsplash

Photo by Yanguang Lan on Unsplash

Why is it important?

The Great Barrier Reef has been experiencing recurrent widespread mass coral bleaching events that have only been increasing in magnitude, frequency, duration, and spatial extent. Previous studies have focused on sea surface temperatures. By exploring the mechanisms that potentially insulate, or protect, deeper reefs from heatwaves occurring in the surface waters, we are able to identify regions, based on robust physical understanding, where management of non-climatic coral stress could allow preservations of a subset of reefs while society rapidly decarbonizes.

Perspectives