An eerie discovery of structures at the bottom of an iconic US lake could unravel mysteries about the unchartered lakebed.
Researchers were mapping an area of Lake Michigan that’s home to at least 36 shipwrecks when they discovered strange depressions hundreds of feet under water.
Scientists are hesitant to describe the strange circles as sinkholes, which have previously been found in Lake Huron, but said they’re more akin to craters.
So far, researchers have found 40 holes, measuring between 500 and 1,000 feet in diameter and 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 determined they are not man-made.
Scientists at the Great Lakes Environmental Research Laboratory (GLERL) surveyed the lakebed on August 21 using a remotely operated vehicle to confirm that the circles are massive, naturally-occurring craters – each about the same size as an Olympic swimming pool.
‘This is a whole new avenue of research. I mean, there’s now a geological question in mind. How did they form? Why are they there, specifically in the bedrock?’ Wisconsin Maritime Museum Director Kevin Cullen told TMJ4 News.
‘We’re all scratching our heads wondering, what could these things be?’
The craters were discovered 450 feet below the water’s surface and about 14 miles southeast of Sheboygan, Wisconsin.
They extend southward toward Port Washington in the Wisconsin Shipwreck Coast National Marine Sanctuary and although the scientists have found 40 of these sinkholes, researchers believe there’s more.
‘Any kind of new discovery in the Great Lakes is exciting,’ Russ Green, a maritime archaeologist and superintendent of GLERL told Live Science.
‘But these features really stand out — they are in deeper water – 500 feet – and weren’t known before, as far as we can tell.’
Researchers used a remotely operated vehicle to survey the lakebed to confirm the massive circles seen in 2022 were actually craters
A team of researchers at the Great Lakes Environmental Research Laboratory reported that 40 sinkholes were discovered, but it is likely there are more
Part of Lake Michigan sits on limestone, making it likely that some of the craters are like the sinkholes found in Lake Huron in 2001.
Limestone can form sinkholes when it dissolves and cracks, allowing the land above it to collapse or sink into the cavities.
However, researchers are refraining from calling the depressions sinkholes until more studies have been conducted.
‘I think they might be more accurately called craters, which have formed in the deep bottom sediment due either to water upwelling from below or trapped hydrocarbon offgassing,’ Brendon Baillod, a local shipwreck hunter who also found several depressions told Live Science.
Researchers reported that it’s unclear when or how the depressions formed, but they provide such extreme environments that it could mimic the early conditions on Earth because of the limited oxygen and sulfur-rich conditions.
This kind of environment is incredibly unique and can help scientists learn more about how Earth evolved before there was oxygen.
‘It’s an extreme environment,’ Greg Dick, a professor at the University of Michigan and director of the Cooperative Institute of Great Lakes Research told the Milwaukee Journal Sentinel.
‘We typically have to go to Antarctica or Yellowstone National Park or some exotic location to get these extreme ecosystems, but this is in our backyard in the Great Lakes.’
There is still very little known about the Great Lakes, as only about 15 percent of all five lakebeds have been mapped.
Scientists have clarified that they know more about the surface and ecosystem on Mars than they do about the Great Lakes.
‘We’ll be exploring them for years to come to learn more, and sort out how they got there and what role they play in Lake Michigan’s ecosystem,’ Green told Live Science.
