About 2,300 miles east of Florida, near an underwater mountain range, lies a unique site teeming with microscopic life. Known as the “Lost City Hydrothermal Field,” it stretches along the Mid-Atlantic Ridge, 2,600 feet beneath the ocean’s surface. Coated in calcium deposits, the area has a haunting beauty, with towering carbonate structures and calcite vents that host rare microorganisms feeding on hot gases. Discovered in 2000 by researchers from the University of Washington and the Woods Hole Oceanographic Institution (WHOI), this vent system offers fascinating insights into the possible origins of life.
“This new venting system, called Lost City was unlike any place ever previously visited. Investigation of this site is changing our views not only about the conditions under which life can thrive on our planet but on others as well,” NOAA writes on its website. The “Lost City” is the longest-lived venting environment known in the ocean. The city is sprinkled with natural rocky sculptures that range in height anywhere from tiny stacks the size of toadstools to a grand monolith standing 60 meters (nearly 200 feet) tall and named “Poseidon.”
In this bizarre city, for millions of years, chemical reactions have been going on between the mantle rocks and the seawater. The reaction spews out enormous quantities of gases like hydrogen and methane into the ocean. These gases act like food for the microbial residents who survive and thrive in the cracks and crevices of the field’s vents.
The most interesting thing is that hydrocarbons here are formed not by atmosphere or sunlight, but by these reactions occurring on the seafloor, that release the gases trapped inside rocks. These microscopic organisms have learned to survive in hostile environments, even without oxygen. They derive some energy from seawater and some from hydrocarbons. “It’s the closest thing to a free lunch the universe provides,” microbiologist William Brazelton told The Smithsonian. This fascinating mechanism could provide some groundbreaking insights into the origin of life.
At the tops of the rocky towers, there are hot chimneys, inside of which reside colonies of nano-sized creatures like snails and crustaceans. In some places, there are considerably large-sized animals such as crabs, shrimp, sea urchins, and eels.
The waters rolling inside the Lost City generally carry a temperature around 200°F, which is cooler than the fluids found in the black smokers because it is not heated by magma; rather, the heat comes from serpentinization, a chemical reaction between seawater and mantle rock. “The reaction between the rock and seawater produces 10 to 100 times more hydrogen and methane (a hydrocarbon) than a typical black smoker system found along volcanic mid-ocean ridges,” as Giora Proskurowski and Deborah Kelley, two authors of a paper in the February issue of the journal Science, explained.
Unlike black smokers, which are underwater volcanic jets, the Lost City’s ecosystem doesn’t depend on the formation of magma. Plus, the calcite vents of Lost City have survived longer than any other like it in the world.
Since hydrocarbons are the building blocks that gave birth to life, the discovery of life in this strange habitat of ‘Lost City’ indicates the possibility that there might be life somewhere else humans have never expected. If a similar kind of habitat is there on Earth, or even on some other planet, it is possible that microscopic life could survive there as well. “This is an example of a type of ecosystem that could be active on Enceladus or Europa right this second,” Brazelton told The Smithsonian, referring to the moons of Saturn and Jupiter. “And maybe Mars in the past.” Proskurowski also proclaimed, “The detection of these organic building blocks from a non-biological source is possible evidence in our quest to understand the origin of life on this planet and other solar bodies,” per WHOI.
Meanwhile, just northeast of these towers, researchers arrived at a cliffside. According to ScienceAlert, they described 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.” After the initial discovery of the Lost City, researchers went back there once more in 2003 for a 19-day expedition using the 3-person submersible Alvin, where numerous samples of rocks, fluids, and biology were recorded for analysis.
In 2018, when Poland won the rights to mine the deep sea around Lost City, some scientists warned that there could be dire consequences. Any plumes of toxic gases or ejection of radioactive materials released during the mining could easily trigger the destruction of this city’s magnificent habitat. Some scientists even urged the higher officials to list the Lost City as a World Heritage site, to protect the natural wonder before it’s too late.
