CO2 dissolves coral ‘before our eyes’
Business-as-usual carbon dioxide emission rates predicted for the latter half of this century will cause major disruptions to coral reefs worldwide, experts predict.
A simulation of future ocean conditions finds coral reefs dissolve rapidly once exposed to warmer, more acidic ocean conditions. Even under fairly low emission scenarios, most corals bleached and died, says Sophie Dove, associate professor of biological sciences at the University of Queensland.
“Given corals are essential to coral reefs, this is not good news,” she says.
For a new study published in the Proceedings of the National Academy of Sciences, Dove and colleagues used computers to control CO2 content and temperature of water flowing over small patches of coral reef at Heron Island on Australia’s Great Barrier Reef.
One of the most significant challenges of climate change is being able to accurately reduce future uncertainties, she says.
“By simulating future environments above complex reef systems, we come closer to understanding what might happen as the oceans warm and acidify.
“If we can reduce the uncertainty, then we have a much better chance of making better decisions to help protect and conserve these valuable ecosystems.”
The study also shows that increases in ocean temperature and acidity not only leads to a reduction in calcification, the process by which corals build coral reefs, but also the rate at which coral reefs dissolve.
“We discovered that coral reefs under the business-as-usual-emission scenario, the one we are on, show high rates of decalcification,” Dove says.
“Essentially, it’s dissolving before our eyes over a few months. This has serious implications for the role of coral reefs in providing habitat for thousands of species and their role in protecting coastlines from wave impacts.”
“One of the key messages of this study is that coral reefs are under even greater threat from ocean warming and acidification than we first thought,” says Ove Hoegh-Guldberg of the Global Change Institute.
“This sounds gloomy but our study also emphasizes the fact that there is time and that small amount of effort today can have a huge impact on what happens in the future.”
The University of Queensland’s Australian Research Council’s Centre for Excellence in Reef Studies and the Great Barrier Reef Foundation funded the study.
Source: University of Queensland