The Great Barrier Reef Is Becoming More Heat-Resistant--at a Price
Source: Gizmodo
The Great Barrier Reef Is Becoming More Heat-Resistant—at a Price
Maddie Stone
Today 11:00am
In 2016 and 2017, disaster struck the world’s largest living structure: back-to-back heat waves caused half of all corals on the 1,400-mile-long Great Barrier Reef to die. But there’s a glass-half-full perspective on this grim news, which is that half of the reef’s corals—approximately 10 billion of them—are still alive. And they just went through one hell of a natural selection event.
Research published today in Nature Climate Change puts a new spin on the worst die-off to roil the Great Barrier Reef in recent memory, by showing that the ecosystem is exhibiting an emerging resilience to rising temperatures. Reefs that cooked and bleached during the summer of 2016 could tolerate much more heat in 2017 without experiencing the same effects. The study’s authors believe we’re witnessing the emergence of an “ecological memory,” wherein response to one climate shock dampens the effect of the next one.
When ocean temperatures crank up too high, it causes corals to jettison the algae that live inside them and provide them with food, turning their jewel-toned exoskeletons a sickly white. This is known as bleaching, and if a coral stays bleached for too long, it begins to starve. Alternatively, if water temperatures are way too hot, corals will simply cook.
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While it’s heartening that not all corals are equally doomed in our warming world, it’s also crucial to note that not all corals play the same ecological role. As Hughes and his colleagues noted in a paper out earlier this year, the Great Barrier Reef is fast becoming a “highly altered, degraded system” as the corals that provide the most nooks and crannies to shelter reef fish vanish.
Hughes predicts that the corals that will be the ultimate winners in our hotter future are slow-growing, hemispherical brain corals and Porites, which he described as good at protecting shorelines but not so great at supporting biodiversity.
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Read more: https://earther.gizmodo.com/the-great-barrier-reef-is-becoming-more-heat-resistant-1830936079
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Related: Ecological memory modifies the cumulative impact of recurrent climate extremes (Nature Climate Change)