
Great Barrier Reef’s blue hole, image courtesy of J. Gaskell
The largest coral reef ecosystem on earth, the Great Barrier Reef, has revealed a spectacular and previously unknown jewel. The sapphire-hued blue hole was discovered by marine biologist and underwater photographer, Johnny Gaskell.
Blue holes are underwater sinkholes. They are formed when carbonate bedrock drops deeper than the surrounding seafloor. Blue holes are characterised by their depth in relation to the surrounding limestone or coral reef bedrock and their spectacular deep blue tone. Notable blue holes are the Dragon Hole (a whopping 300m deep) and the 300m wide Great Blue Hole of Belize.
Gaskell, a resident of the Whitsunday’s, described his find on his Instagram account, “After spotting this deep blue hole on Google Maps we decided to head far offshore, out further than our normal Reef trips to see what dwelled within.” And what a find it was! At depths of 15-18m the divers discovered pristine colonies of giant birdsnest and unusually long Staghorn corals.
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