Scientists have discovered more than 4,500 mysterious holes off the coast of Big Sur, California. These craters, known as 'micro depressions' were discovered during a series of underwater surveys conducted between 2018 and 2019. The discovery was made by researchers at the Monterey Bay Aquarium Research Institute in Moss Landing, California, who were studying North America's largest pockmark, a giant crater that stretches 60 feet across the seabed.

What caused these mysterious holes in the floor?

Researchers, after analyzing these mysterious holes revealed that they were created by human garbage. As per close observations in the seafloor, experts understood that marine trash is responsible for these tiny pits, and most of them had the size of a bus, filled with plastic wastes, nets, ropes and several other garbages.

However, researchers did not find any evidence that indicates the origin of these craters due to fluid or gas venting in the recent past. Even though scientists assure garbages as the cause of tiny craters, they are still unclear regarding the origin of giant craters in the seafloor.

Mystery holes in seafloor
Holes in seafloor off California Monterey Bay Aquarium Research Institute

Mapping and radiocarbon dating conducted on these craters reveal that these structures were formed at least 4,00,000 years ago.

"The pockmarks and micro-depressions in this area are both holes in the seafloor that occur in softer sediments, but they are morphologically distinct. The cause and persistence of the pockmarks still remain a mystery, but we find no evidence they were created from gas or fluid in the seafloor in the recent past. The micro-depressions are recently formed erosional features; they are not 'incipient pockmarks," said Eve Lundsten, the archer who led the survey in a recent statement.

The mysterious Baltic Sea anomaly

It was in 2011 that researcher Peter Lindberg, Dennis Åsberg and their Swedish 'Ocean X' team discovered the Baltic Sea anomaly, and since then, the origin of this anomaly has been perplexing marine experts. During their research, explorers discovered a weird object with unusual features resting on the floor of the Baltic Sea.

After the discovery, several conspiracy theorists started arguing that this mysterious object could be an alien spaceship that might have crash-landed on the sea. However, some other experts believe that this anomaly could be either an underwater bunker built during the second world war, or it might be a purely natural phenomenon.