What corals can tell us about climate change

Scientists are using corals from the Cayman Islands to get a glimpse into Caribbean Sea temperatures over the past 500 years—critical information in predicting the effect of climate change on coral reefs. “Corals are very important for the ocean ecosystem. Upwards of 60 per cent of ocean species live in coral reefs,” said Simone Booker, PhD student in the University of Alberta’s Department of Earth and Atmospheric Sciences and lead author of the paper. “In this study, we’ve looked at how corals have responded to high sea temperatures in the past, giving us a better understanding of how the reefs that depend on them will fare in the future.” Corals grow in layers, similar to tree rings, and are highly sensitive to ocean conditions. Using X-rays and computerized tomography (CT) scans, the scientists were able to identify four distinct phases of ocean temperature changes, including a drastic increase from 1932 to 2006, with a milder rise from 2006 to 2014. 

“With our current global climate variability, a lot of corals are bleaching due to high sea temperatures—an indicator of poor coral health that can lead to death,” explained Booker. “There’s a distinct need to understand how these rising temperatures will affect reef health in the future.”