A submarine team delved into the mysterious depths of Belize’s Great Blue Hole to discover what’s lying hidden in the areas light doesn’t reach.
Scientists recently set out to search the gaping sinkhole, which is a UNESCO World Heritage site and measures 300 meters (984 feet) in width, and reaches a depth of 124 meters (407 feet).
Earlier this year, the team shone a light into the hole to discover what lay beneath, and they were met with a saddening scene when they found plastic littering the site.
But there were depths the light couldn’t reach, and so the researchers had to try a different method to figure out what the ocean was concealing.
In a blog post, Erika Bergman, oceanographer and the chief submarine pilot on the expedition, explained by using sonar, the team were able to produce a three-dimensional image of the sinkhole.
They focused on certain points of interest, including stalactite caverns formed when sea levels were lower, and the hole was a dry cave, which have now been encrusted by marine growth.
At 290 feet deep the team found a calcium carbonate layer where a coral reef used to grow, and at 407 feet they found evidence of some small stalactite and stalagmite formations, which had been covered in sand over time.
Data found below a hydrogen sulfide layer at 300 feet, the hole is completely anoxic, meaning there’s not a single drop of oxygen in the water.
The lack of oxygen was also evidenced by a ‘conch graveyard’, which Bergman described as ‘a stretch of the blue hole where we observed hundreds of dead conch that had presumably fallen in to the hole’.
We can see each conch with little tracks back up the hill trying to escape, then a slide mark where it slid back down after presumably being asphyxiated in the anoxic environment.
It doesn’t sound like a pleasant end for the poor conch.
Bergman called the hole ‘otherwordly’, and it certainly sounds it!
A creepy conch graveyard isn’t quite what springs to mind when you picture the luxurious Caribbean sea.
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