Sometimes, change is good.

Scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science have discovered a new resiliency in certain coral reefs in the tropical Pacific Ocean. Dominant, foundational coral species on those reefs have survived multiple marine heat waves so far by changing out the symbiotic algae within their cells to build heat tolerance. This adaptation could help those reefs survive into the 2060s – well beyond current projections for coral reefs as a whole.

Coral reefs are rich and vital marine ecosystems. Despite taking up less than 1% of the ocean floor, they are home to more than 25% of all marine life – providing food, shelter and habitat. In fact, coral reefs could be the most biodiverse ecosystem on the planet – even edging out tropical rainforests.

Individual coral colonies are made up of “duplicated” individual coral polyps, which replicate themselves to create massive structures and reefs. Each coral polyp, itself a complete animal, contains symbiotic algae called zooxanthellae. The microscopic algae photosynthesize and provide corals with energy that the hosts use to grow. In exchange, the algae have a safe place to live within the corals and use their hosts’ waste to photosynthesize.

Climate change is causing water temperatures to increase to unprecedented levels, threatening coral health worldwide. Typically, as water temperatures increase, corals expel their helpful algae (which also give them their namesake colors) and “bleach.” Without the energy provided by zooxanthellae, the corals turn white, struggle to meet their energy needs and often die. According to The Independent, Earth has already lost more than half of its “underwater rainforests” and over 90% will die by 2050. Along the same lines, the World Economic Forum reported that 99% of coral reefs could disappear without drastic climate action in this decade.

Understanding how and why changes in this symbiotic relationship occur led the UMiami scientists to their new discovery. Their findings – that some corals can shuffle symbionts to increase heat resistance in the face of climate change – offer a “ray of hope” against this dominant and depressing coral narrative.

Read the full article about coral reef resilience by Tiffany Duong at EcoWatch.