There's a "lost city" at the bottom of the ocean, and it's unlike anything we've ever seen

There’s a “lost city” at the bottom of the ocean, and it’s unlike anything we’ve ever seen

Near the top of an undersea mountain west of the Mid-Atlantic Ridge, a jagged landscape of towers rises from the darkness.

Their creamy carbonate walls and columns appear ghostly blue in the light of a remote-controlled vehicle sent out to explore.

Their height varies from tiny piles the size of mushrooms to a large monolith 60 meters (nearly 200 feet) high. It is the lost city.

A remote-controlled vehicle illuminates the spiers of the lost city. (D. Kelley/UW/URI-IAO/NOAA).

Discovered by scientists in 2000, more than 700 meters (2,300 feet) below the surface, the Lost City hydrothermal field is the longest-lived venting environment known in the ocean. Nothing else like it has ever been found.

For at least 120,000 years and possibly longer, the rising mantle in this part of the world has reacted with seawater to push hydrogen, methane and other dissolved gases into the ocean.

In the cracks and crevices of the field’s vents, the hydrocarbons feed new microbial communities even without the presence of oxygen.

Bacteria on calcite column.
Strands of bacteria living on a calcite vent in the Lost City. (University of Washington/CC BY 3.0).

Chimneys spitting gases up to 40°C (104°F) are home to an abundance of snails and shellfish. Larger animals such as crabs, shrimps, sea urchins and eels are rare, but still present.

Despite the extreme nature of the environment, it appears to be teeming with life, and researchers believe it deserves our attention and protection.

While other hydrothermal vents like this probably exist elsewhere in the world’s oceans, it’s the only one remotely operated vehicles have been able to find so far.

The hydrocarbons produced by the Lost City vents did not form from atmospheric carbon dioxide or sunlight, but through chemical reactions on the deep seabed.

Because hydrocarbons are the building blocks of life, it leaves open the possibility that life originated in a habitat like this. And not just on our own planet.

“It’s an example of a type of ecosystem that could be active on Enceladus or Europa right now,” said microbiologist William Brazelton. The Smithsonian in 2018, referring to the moons of Saturn and Jupiter.

“And maybe Mars in the past.”

Unlike the underwater volcanic vents called black smokers, which have also been named as the earliest possible habitat, the ecosystem of Lost City does not rely on the heat of magma.

Black smokers mainly produce minerals rich in iron and sulfur, while the chimneys of Lost City produce up to 100 times more hydrogen and methane.

Lost City’s calcite vents are also much, much larger than the black smokers, suggesting they’ve been active longer.

Grand Vent of the Lost City
Nine meter high chimney in the Lost City. (University of Washington/Woods Hole Institute of Oceanography).

The tallest of the monoliths is called Poseidon, after the Greek god of the sea, and stands over 60 meters high.

Just northeast of the tower, meanwhile, is a cliff with short bursts of activity. University of Washington researchers describe the vents here as “weeping” with fluid to produce “clusters of delicate, multi-pronged carbonate growths that extend outward like the fingers of upturned hands.”

Unfortunately, scientists aren’t the only ones drawn to this unusual terrain.

In 2018, it was announced that Poland had obtained the rights to exploit the deep sea around The Lost City. While there are no valuable resources to extract from the heat field itself, destroying the city’s surroundings could have unintended consequences.

Any plume or release, triggered by mining, could easily spill over this remarkable habitat, scientists warn.

Some experts are therefore calling for the lost city to be listed as a World Heritage Site, in order to protect the natural wonder before it is too late.

For tens of thousands of years, the lost city has stood as a testament to the enduring force of life.

It would be like us to spoil it.

An earlier version of this article was published in August 2022.

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