Coral Bleaching of World’s Southernmost Reef Blamed on Climate Change
The southernmost coral reef of the world isn’t looking too pretty.
Where is this reef? It’s located near Lord Howe Island, which is off the eastern coast of Australia. Warming seas have caused bleaching of this particular reef for the first time ever. Coral bleaching (or whitening) occurs when the algae-like protozoa dies or is expelled from the coral for stress-related reasons. Yes, coral gets stressed out. A particular type of protozoa, called zooxanthellae, is what gives the coral its coloring. When these are expelled, the coral begins to lose its color.
Australian scientist, Pete Harrison, has monitored the island for the past 17 years. He noted that a 4 degrees F (2 C) rise in sea temperatures had significantly drained the reef of its colors. Along with his team from Southern Cross University, Harrison surveyed the reef this month. The reef—located approximately 370 miles (600 km) east of Sydney—was unusually warm. Harrison speculates the water traveled down from tropical seas near the Great Barrier Reef. He explained:
“We’re hoping the vast majority of these corals will be able to recover, but at the moment this whole system is on a knife-edge and we don’t know what’s going to happen.”
Harrison blames climate change for the bleaching; however, he said the reef can survive—if the water temperatures return to normal quickly enough. Unfortunately, if the bleaching becomes too severe, it will take decades for the reef to recover. Other marine creatures that depend on the reef are also suffering, including anemones and fish.
Harrison put the situation into perspective with one other statement:
“It’s exactly what you predict from warming seas. This is a warning of likely future increases of stress on this world’s southernmost reef.”
By Heidi Marshall