Is Earth IMPLODING Beneath the Ocean? | Unexplained Sinkholes | Unveiled

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The Unexplained Formation of Undersea Sinkholes: What is Happening to Earth?</H4>

The oceans hold many mysteries we’re still trying to unravel. But while lots of us want to know what secrets lie in its deepest points, there are things just as strange in the shallows. And sometimes, these bizarre formations can be clearly visible without diving below the surface at all.

This is Unveiled, and today we’re answering the extraordinary question: what are these unexplained undersea sinkholes, and what do they mean for Earth?

The sea, from the choppy waves on the surface to the deepest depths, plays host to many strange phenomena. It’s long proven dangerous, not only to sailors venturing into treacherous waters, but also to people living on the coast. Many cultures have had flood myths, dating back thousands of years, including the oldest piece of literature that survives to this day, the Mesopotamian Epic of Gilgamesh. A flood myth is also a major part of the Book of Genesis and the legend of Atlantis. People fear the power and might of the sea, and that could be why these vast, underwater sinkholes are so extraordinarily unsettling.

The most famous underwater sinkhole is the Great Blue Hole just off the coast of Belize in Central America, in a small atoll called Lighthouse Reef. Because of its position in an otherwise shallow, idyllic corner of the Caribbean, with other parts of the reef being used as popular diving spots, the Great Blue Hole has attracted a lot of attention. Due to its depth of over 400 feet, it looks significantly darker than the pale coral reef and shallow water around it. It’s also home to diverse sea life and the entrance to an extensive underwater cave system. The spot is popular with scuba divers, although it isn’t without danger. Three divers have disappeared inside, although only two bodies have been found. 

Another famous blue hole like this is just north of Dahab, Egypt, on the coast of the Red Sea that separates Egypt from Saudi Arabia. Simply called the Blue Hole, it’s much less striking to look at but significantly more dangerous. As many as 200 divers may have perished within, despite its unassuming appearance. If you didn’t know what it was and looked at it from the coast, you’d have no idea it was over 300 feet deep. The likely cause for the deaths is that the Blue Hole has a tunnel entrance called the Arch, and in the past, inexperienced divers would get lost and tragically lose their lives trying to swim through it. 

There are many more blue holes, too, including one named the Dragon Hole in the South China Sea, the deepest anywhere in the world at nearly 1,000 feet. And there are multiple blue holes around the Bahamas in the Caribbean. In fact, it’s thought that there may be over 1,000. And so far, we’ve only explored around 200 of them. 

But what are these ‘submarine sinkholes’? Is there something more sinister going on? Well, interestingly, many of these sinkholes – including the one in Belize – were created thousands of years ago, when planet Earth was in the grip of the last ice age, which lasted from around 115,000 to  11,500 years ago - peaking 20,000 years ago. 

Back then, sea levels were much lower, because so much of Earth’s water was frozen. It’s believed by scientists that most of these holes were created through Karst processes. In a nutshell, this is when certain types of rock are dissolved by water. Usually, this involves carbonate rock, often limestone, being slowly dissolved by rain, back when these regions of the planet were still high above the water’s surface. As we mentioned, the Great Blue Hole exists in the heart of Lighthouse Reef, and Lighthouse Reef is a carbonate platform. So, it’s made of those very same carbonate rocks that are so easily dissolved. In fact, most of the most notable coral reefs in the world, including the Great Barrier Reef in the Coral Sea of the South Pacific, are on carbonate platforms, made up of the ancient skeletons of simple organisms. During the ice age, rainfall was all that was needed to dissolve the carbonate and create these enormous cave systems that were then filled in by water as all the ice melted.

Thankfully, this is much less dramatic than the mechanisms that have been making new sinkholes on land, sometimes called “exploding craters”. It’s been a popular news topic in recent years, as new sinkholes appear in the Arctic Circle, largely Siberia. As permafrost melts, methane deposits have been expanding and exploding. They create huge, underground voids that then collapse into dangerous sinkholes, some of which are still growing and threatening nearby communities. This is a frightening consequence of global climate change, driven by human activities. While underwater sinkholes are also the result of warming after the last ice age, this was part of a natural - and much more gradual - process. 

Having said that, some blue holes do seem to have formed through means other than Karst processes. When sinkholes are produced through Karst processes, it also creates many additional, smaller tunnels, sometimes building massive cave systems. However, not every blue hole has these smaller tunnels - some are simply deep shafts in the shallows. Some studies suggest they may have been created by other mechanisms, like the sheer force of the tides, but more research needs to be done. That’s part of what makes the blue holes so enticing - not just to divers looking for a unique, otherworldly experience, but for scientists the world over.

So, what can we learn by studying blue holes? Well, one major thing is that they can teach us about what the world was like long before human exploration. Some of these holes are so deep and have been home to life for so long that the bases are full of preserved fossils. Remember, these blue holes form in coral reefs, some of the most diverse places on our planet – they’re not void of life, despite being dark and strange to us here on land. Animals live out their entire lives in and around these holes and then, when they die, they sink to the bottom, creating layers of long-dead creatures. This sounds a little macabre, but studying those fossils with submersibles and careful excavation can tell us so much about ocean diversity and what kind of ecosystems have formed in these unique conditions. Bizarrely, even tortoise fossils have been found in those holes, which is especially interesting since tortoises all live on land. The strange conditions in the holes are what keep fossils so well-preserved. It’s thought that the diversity of life in these cavities is many times greater than even coral reefs themselves, and much weirder.

Though it may not initially be as exciting as finding the remains of a huge dinosaur down there, scientists have also discovered unique bacterial colonies that feed on sulfur. The holes are full of sulfur because of the large numbers of dead animals that have been living and dying down there for such a long time. These remains release sulfur, making the water toxic for lots of creatures. Certain kinds of bacteria on the other hand thrive in these conditions, showing again the sheer stubbornness of life on Earth to adapt and keep going even when everything says it should be killed off. Could exploring the blue holes then be a way to prepare for investigating alien ecosystems in the future? Saturn’s largest moon Titan, for instance, has lakes of liquid hydrocarbons, specifically ethane and methane. Could natural processes create blue holes in liquid hydrocarbons, similar to their occurrences in oceans? Some of Titan’s lakes are vast, and if any life has ever been able to form on the moon, it could have done so there. If bacteria can thrive on poisonous, oceanic sulfur, then maybe it could do so on poisonous, oceanic methane and ethane just as well. In this way, perhaps the blue holes are, like other extreme environs on our home planet, a great way to prepare for studying distant moons in search of extraterrestrial life.

What’s your verdict? Would you ever dive into a deep blue hole, or would you stay safely on the coast? And how much time and effort do you think we should spend exploring them?

Ultimately, the blue holes are fascinating, relatively small, and partially isolated biomes that have been able to create unique microbial environments in the many millennia since the last ice age began to thaw. And that’s the mystery behind these unexplained, underwater sinkholes.