Mysterious hole found in Great Barrier Reef leads to incredible discovery
Scientists exploring a giant blue hole in the Great Barrier Reef just made a shocking discovery. The hole – around 125 miles (200km) from Daydream Island, north east Australia – has previously only been described by geologists.
Little is known about it, but an initial exploration by divers suggests that despite extensive coral bleaching elsewhere on the reef – the blue hole contains a mass of healthy coral colonies. Johnny Gaskell, a marine biologist from the Whitsundays, Australia, shared a stunning image of the hole on his Instagram page. He said: ‘This blue hole has previously been described by geologists who suggested it could be even older than the famous Great Blue Hole, in Belize. ‘Its location is in one of the least explored parts Great Barrier Reef, over 200km from Daydream Island. ‘To get there we had to travel overnight for 10 hours and time the tides perfectly. Was well worth it.’ A blue hole is a marine sinkhole that extends well below sea level for most of its depth. The formations were created during past ice ages, when the sea level was as much as 100-120 metres lower than today. What is Coral bleaching? Coral bleaching results in white bleached-out reefs – losing their brilliant colours. The colour of coral comes from tiny algae that live in its tissues. But elevated sea temperatures – often due to climate change – makes the coral too hot and the algae get ejected, turning them white. Without the algae, the coral cannot survive. Over time, glacial runoff began dissolving the limestone ground, forming sinkholes with massive caverns below. The roofs of these caverns would eventually collapse, leaving deep holes in their wake.
Johnny’s team of divers explored just over 20 metres (65 feet) down into the blue hole, before hitting sand. When they got down there, the divers discovered coral that had now been affected by bleaching. ‘It was great to see big healthy coral colonies,’ Johnny said.
The discovery of healthy coral in the blue hole may come as a surprise to experts, following extensive coral bleaching elswhere in the Great Barrier Reef. The reef has been hit by two successive bleaching events in 2016 and again earlier this year, with experts concerned about the impact of global warming on the natural wonder. Bleached states can last for up to six weeks with some corals able to recover if the temperature drops – but severely bleached corals will die off. The discovery of healthy coral in the sinkhole raises hopes for the rest of the Great Barrier Reef.