A grisly discovery of structures at the bottom of an iconic American lake could unravel mysteries about the unknown bottom.
Researchers were mapping an area of Lake Michigan that contains at least 36 shipwrecks when they discovered strange depressions hundreds of feet underwater.
Scientists hesitate to describe the strange circles as sinkholes, which have previously been found in Lake Huron, but say they look more like craters.
So far, researchers have found 40 holes with a diameter between 150 and 300 meters. They hope that further observations will reveal how Earth evolved to support life.
Scientists have discovered 40 craters about 450 feet below the surface of Lake Michigan
The giant holes found at the bottom of Lake Michigan were first spotted by sonar images two years ago, and recent findings have shown they are not man-made.
Scientists from the Great Lakes Environmental Research Laboratory (GLERL) examined the lake bottom on August 21 using a remotely operated vehicle to confirm that the circles are enormous, naturally occurring craters – each about the size of an Olympic swimming pool.
‘This is a completely new research direction. I mean, there’s a geological question in mind now. How did they originate? Why are they there, especially in the bedrock?’ Kevin Cullen, director of the Wisconsin Maritime Museum, said TMJ4 News.
“We’re all scratching our heads wondering, what could these things be?”
The craters were discovered 450 feet below the surface and about 14 miles southeast of Sheboygan, Wisconsin.
They extend south toward Port Washington in the Wisconsin Shipwreck Coast National Marine Sanctuary and although scientists have found 40 of these sinkholes, researchers believe there are more.
“Any new discovery in the Great Lakes is exciting,” said Russ Green, maritime archaeologist and GLERL superintendent. Living Science.
“But these features really stand out: they are in deeper water – 150 meters – and to our knowledge were not previously known.”
Researchers used a remote-controlled vehicle to examine the lake bottom and confirm that the massive circles seen in 2022 were actually craters
A team of researchers from the Great Lakes Environmental Research Laboratory reported that 40 sinkholes have been discovered, but it is likely that there are more.
Part of Lake Michigan lies on limestone, making it likely that some craters resemble the sinkholes found in Lake Huron in 2001.
Limestone can form sinkholes when it dissolves and cracks, causing the land above it to collapse or sink into the cavities.
However, researchers are refraining from calling the depressions sinkholes until more studies are conducted.
“I think they might be more accurately called craters, which formed in the deep bottom sediment as a result of the upwelling of water from below or the off-gassing of hydrocarbons,” Brendon Baillod, a local shipwreck hunter who also found several depressions, told LiveScience .com.
Researchers reported that it is unclear when and how the depressions formed, but they provide such extreme environments that they could mimic early conditions on Earth due to the limited oxygen- and sulfur-rich conditions.
This type of environment is incredibly unique and could help scientists learn more about how Earth evolved before there was oxygen.
“It’s an extreme environment,” said Greg Dick, a professor at the University of Michigan and director of the Cooperative Institute of Great Lakes Research. Milwaukee Journal Sentinel.
“Normally we have to go to Antarctica, Yellowstone National Park or some exotic location to find these extreme ecosystems, but this is in our backyard, in the Great Lakes.”
Still very little is known about the Great Lakes, as only about 15 percent of all five lakes have been mapped.
Scientists have made it clear that they know more about the surface and ecosystem on Mars than they do about the Great Lakes.
“We’ll be studying them over the next few years to learn more, and find out how they got there and what role they play in the Lake Michigan ecosystem,” Green told LiveScience.