Government scientists are “stumped” by a tidy trail of holes that they spotted on the seafloor, more than a mile under the ocean surface, during a recent dive, according to a tweet from the National Oceanic and Atmospheric Administration (NOAA), a U.S. federal agency.
“The holes look human made, but the little piles of sediment around them suggest they were excavated by…something,” NOAA said on Twitter.
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The unexplained holes were discovered and imaged on Saturday by a remotely operated submersible as part of NOAA’s second Voyage to the Ridge 2022 expedition, which is currently exploring and mapping a region of the Mid-Atlantic Ridge, an immense underwater mountain range, north of the Azores archipelago.
“During Dive 04 of the second Voyage to the Ridge 2022 expedition, we observed several of these sublinear sets of holes in the sediment,” NOAA scientists said in a statement. “These holes have been previously reported from the region, but their origin remains a mystery.”
Indeed, in 2003, scientists reported the discovery of similar tracks of holes, around the same area, in the journal Frontiers in Marine Science. The researchers speculated that raised sediment around the holes indicated they could have been dug out by deep sea crustaceans, such as the blind lobster (Acanthacaris caeca), or perhaps excavated by animals living inside the seafloor. Ultimately, though, the authors of that study were as stumped as the current NOAA expedition team about the origin of the “lebensspuren,” which is the term for biological formed structures such as holes and burrows.
“The source of the holes or how they were constructed is unknown,” said the researchers in the study. “None of our closeups showed any sign of living organisms inhabiting the holes. Whether the holes were connected beneath the sediment surface was not visible….We hope that future studies of the lebensspuren we report here will resolve the mystery of what created them.”
These enigmatic seafloor tracks are just one of the many marvels that have been uncovered by NOAA’s Ocean Exploration program, which often offers live footage of its marine missions on YouTube.
In addition to the strange tracks, the ongoing Voyage to the Ridge 2022 expedition has observed eerie deep-sea animals—such as grenadiers, squat lobsters, and bright-crimson small jellies—and has helped to shed light on the “unexplored and poorly understood deepwater areas of the Charlie-Gibbs Fracture Zone, Mid-Atlantic Ridge, and Azores Plateau,” according to a NOAA statement.
“Voyage to the Ridge 2022 will seek to close some of these gaps and increase our understanding of the region’s geological context and past and future geohazards, the diversity and distribution of coral and sponge communities, and how populations of deep-sea species are related across this region and throughout the deepwater Atlantic basin,” NOAA said.
