Marine biologists based in the Whitsunday Islands have discovered a previously unknown feature in the Great Barrier Reef: a "blue hole".
If you’re not familiar with the term, a blue hole is a marine cavern or sinkhole, much deeper than the surrounding sea area. They are usually the consequence of erosion during the last Ice Age, when the sea level was lower than today.
“After spotting this blue hole on Google maps, we decided to head far offshore, further than our normal Reef trips to see what dwelled within,” Johnny Gaskell, who discovered it, said in his breathtaking Instagramvideo. “What we found inside was hard to believe considering 5 months ago a category 4 cyclone went straight over the top of it.”
The blue hole seems to have remained undiscovered until Gaskell visited it. He described how it was further out and hidden within one of the reef's biggest lagoons. That a feature such as this has gone unnoticed is actually not that surprising. The Great Barrier Reef stretches for 2,300 kilometers (1,400 miles) along the northeast coast of Australia. The "Great" in its name is not just an honorific title.
“At around 15 to 20 meters deep, there were huge Birdsnest Corals (Seriatopora) and super elongated Staghorn Corals (Acropora), both of which were among the biggest and most delicate colonies I’ve ever seen,” Gaskell continued in the Instagram post. “It’s not as deep as the famous Great Blue Hole in Belize but it is a really unique spot.”
It’s great to hear of the thriving life in this part of the reef. The depth of the hole and its cooler waters protect the many creatures that live within it. And it’s also good to hear some positive stories about the Great Barrier Reef for once. The reef has experienced some terrible years recently, between Cyclone Debbie and the recent bleaching events that have been the worst in recorded history, every reef story is depressing.
According to researchers, 95 percent of the northernmost third of the reef was damaged by the 2016 bleaching event and a second one (which impacted the middle third the hardest) in 2017 was the fatal blow for many corals. Those parts of the reef are now beyond recovery.