Australia. Home to the Great Barrier Reef and many other world-famous coral reefs.
Coral reefs are some of the most biodiverse areas in the world. They only cover 0.1% of the ocean, yet support 25% of global marine species. In recent years, however, they have been affected by coral bleaching.
Coral bleaching is a process that causes corals to lose their colour. When there are abnormal environmental conditions, like warmer sea temperatures, corals expel a photosynthetic alga that usually gives the coral its colour. Without this algae, corals are colourless, or ‘bleached’.
There are a number of regions and locations around Western Australia that are home to coral reefs. In this study, corals in the Kimberley region, Ningaloo and around Rottnest Island were observed and examined (see below).
In 2016, a mass bleaching event had a devastating impact on many of the coral reefs around Western Australia (WA). Research by the University of Western Australia (UWA) found that reefs in the Kimberley region in the north had been affected most, despite these corals being known as stress resistant. It’s believed that 57% to 80% of inshore reefs in this region were bleached and it is unknown how much of that can be saved.
Rottnest Island, just off the coast of Perth, was also affected by the 2016 bleaching event. Approximately 29% of the corals around the island were moderately bleached but can still be saved.
The Ningaloo Reef, which is also a UNESCO World Heritage Site was unaffected by the bleaching event.
2016 saw a particularly strong El Nino climatic event which is believed to have been the cause of coral bleaching event. El Nino events are believed to affect coral reefs in the north of the state more than those in the south, whereas the south sees greater bleaching during La Nina events.
As oceans warm, these El Nino and La Nina climate events will increase in intensity, meaning that without some kind of change these observed bleaching events will become increasingly common and will affect more and more of the corals in WA and around the world.
This goes beyond just being an environmental issue. There are more than 500 million people around the world that rely on fishing in coral reefs and many developing economies rely on fishing as a food source for its population and for exports. If we do nothing to try limit the warming of global oceans, bleaching events like this one in 2016 could become more frequent and much more intense and have many more impacts beyond the environment!