The Mysteries of the Lost City — Mid-Atlantic Hydrothermal Field

Posted on by August 27, 2022

Over two thousand feet beneath the surface of the North Atlantic, on the seamount Atlantis Massif, at the intersection between the Mid-Atlantic Ridge and the Atlantis Transform Fault, a jagged landscape of towers rises from the deep ocean gloom. Discovered in 2000, the Lost City Hydrothermal Field, often referred to simply as the Lost City, is an area of marine alkaline hydrothermal vents. It is the longest-lived venting environment known in the ocean. Nothing else like it has ever been found.

ScienceAlert.com notes that for at least 120,000 years and maybe longer, the upthrusting mantle in this part of the world has reacted with seawater to puff hydrogen, methane, and other dissolved gases out into the ocean. In the cracks and crevices of the field’s vents, hydrocarbons feed novel microbial communities even without the presence of oxygen.

Chimneys spewing gases as hot as 40 °C (104 °F) are home to an abundance of snails and crustaceans. Larger animals such as crabs, shrimp, 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 think it’s worth our attention and protection.

Of the 30 active and inactive vent chimneys, Posidon is the largest and most-studied within the vent field. Posidon stands about 60 metres (200 ft) tall and 100 metres (330 ft) wide and has numerous orifices venting hot fluids.

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

The hydrocarbons produced by the Lost City’s vents were not formed from atmospheric carbon dioxide or sunlight, but by chemical reactions on the deep seafloor.

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

“This is an example of a type of ecosystem that could be active on Enceladus or Europa right this second,” microbiologist William Brazelton told The Smithsonian in 2018, referring to the moons of Saturn and Jupiter. And maybe Mars in the past.”

Unfortunately, scientists aren’t the only ones beckoned by that unusual terrain.

ScienceAlert.com also reports that in 2018, it was announced that Poland had won the rights to mine the deep sea around The Lost City. While there are no precious resources to be dredged up in the actual thermal field itself, the destruction of the city’s surroundings could have unintended consequences.

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