Photographs reveal that the dents punched into an otherwise flat and sandy terrain form interconnected, straight lines, adding to the mystery.
During a dive during the 'Voyage to the Ridge' expedition last summer, researchers discovered a series of sublinear holes over a mile beneath the Atlantic Ocean.
At first glance, the identical-lookin trenches appear to be man-made, with small piles of earth beside them.
However, the crew of the Okenos Explorer could not look inside.
Twelve months on, scientists still can't figure out what they are.
According to a spokesperson from NOAA Ocean Exploration, said: "We observed several of these sublinear sets of holes in the sediment,"
"We observed several of these sublinear sets of holes in the sediment," NOAA Ocean Exploration reported.
"These holes have been previously reported from the region, but their origin remains a mystery."
"While they look almost human-made, the little piles of sediment around the holes make them seem like they were excavated by ... something."
The area where the holes were found spans the north-south length of the Atlantic Ocean. This is where earthquakes occur frequently and hydrothermal vents form as magma rises to the seafloor.
As much of the field remains unexplored, scientists have yet to find an explanation.
Subsequently, the agency posted photos of the discovery on social media and encouraged followers to speculate about the origin of the ‘perfectly aligned’ holes at the bottom of the sea.
One person said: It’s probably some crustacean shellfish that made those. Leave it at that
A second wrote: Could it be that a marine creature has traveled in a straight line, and left indentations?
A third said: Do not delve too deep. Who can tell what nameless horrors we might awaken in the deep places of the earth?
Someone else wrote: So who built these underwater pipes? There must be plans and designs if they built them 1.7 miles beneath the surface.
Another said: Maybe it was caused by a ridged skid on the submersible touching the seabed. Quite recently, a scientific Arctic survey ship reported finding microplastics in the polar seas, only to realize they had come from the paint on its own hull!
Probably a crustal fault line with either gas or water seeping upwards. Another added.
Someone continued: These are mooring points that held the underwater passive microphones to detect Russian submarines in the Cold War. The US put thousands of them in the Atlantic.
In 2004, a group of explorers embarked on a mission to descend more than 2,000 meters along the Mid-Atlantic Ridge, where they discovered several similar indentations.
Michael Vecchione and Odd Aksel Bergstad, both scientists, writing in their papers, offered their own theory as to their origin.
They explained:
"The holes that appeared to be most recently formed were each surrounded by raised sediment. Holes that appeared older were partly filled with sediment and the raised surrounding sediment was less obvious.
"The source of the holes or how they were constructed is unknown, but the raised sediment may indicate excavation by an infaunal organism or digging and removal by e.g., a feeding appendage of a large epifaunal animal."
Watching the video below:
