Deep beneath the surface of the Atlantic Ocean, an ecosystem unlike anything else on Earth has captured the imagination of scientists and adventurers.
Known as the “Lost City,” this otherworldly realm of towering mineral chimneys and bizarre life forms has thrived for over 120,000 years in the darkness of the deep sea.
As researchers explore the secrets of this unique ecosystem, they are not only uncovering clues about the origins of life on our planet but also grappling with the looming threats that could forever alter this underwater wonder. Here’s what they have found so far.
A Hydrothermal Wonderland
Nestled at the intersection of the Mid-Atlantic Ridge and the Atlantis Transform Fault, the Lost City Hydrothermal Field is a sight to behold.
Towering carbonate chimneys, some reaching 200 feet, rise from the seafloor, bathed in an eerie blue light. These structures, formed by the reaction of seawater with the upthrusting mantle rock through a process called serpentinization, have created a unique environment that supports a thriving ecosystem in the absence of sunlight.
The Lost City’s hydrothermal vents are unique to Earth’s oceans. Instead of the mineral-rich, superheated fluids that characterize black smokers, these vents release cooler, alkaline fluids rich in hydrogen, methane, and other low-molecular-weight hydrocarbons. These gases serve as the foundation for the complex microbial communities that call the Lost City home, hinting at the possibility that life on Earth—and perhaps on other worlds—could have originated in similar environments.(ref)
A Haven for Extreme Life
Despite the harsh conditions of the deep sea, the Lost City is teeming with life. From dense colonies of bacteria to more complex organisms like snails, bivalves, polychaetes, amphipods, and ostracods, the creatures that inhabit this underwater oasis have adapted to thrive in an environment devoid of oxygen and sunlight.(ref)
The microbial communities of the Lost City are particularly fascinating to scientists. These hardy microbes, known as extremophiles, have evolved to survive in conditions lethal to most other life forms.
Archaea and bacteria related to methanogens, methanotrophs, sulfur-oxidizers, and sulfate-reducers form thick biofilms inside the vents, subsisting on the hydrogen and methane produced by serpentinization.
While studying these organisms, researchers hope to gain insights into the limits of life on Earth and the potential for life to exist in the extreme environments found on other planets and moons.
A Window into the Past & Future
With an estimated age of at least 120,000 years, this hydrothermal field has endured for far longer than any other known vent system. The longevity of the Lost City suggests that similar environments could have played a crucial role in the origin and evolution of life on Earth billions of years ago.
Moreover, the Lost City is a tantalizing analog for the habitats that might exist in other worlds. The hydrogen- and methane-rich fluids that sustain life in this underwater realm resemble the conditions that scientists believe could support life on ocean worlds like Europa and Enceladus.
By studying the Lost City, researchers are learning about our planet’s history and gaining valuable insights into the potential for life beyond Earth.
An Uncertain Future
Despite its significance and beauty, the Lost City faces an uncertain future. In 2018, Poland secured mining rights to the deep-sea region surrounding the hydrothermal field, raising concerns among scientists and conservationists about the potential impacts of mining activities on this delicate ecosystem. (ref)
While the Lost City itself may not be directly targeted by mining operations, the surrounding area could be subjected to plumes of sediment and other disturbances that could have far-reaching consequences for the creatures that call this place home.
As the demand for deep-sea resources grows, the fate of the Lost City and other unique habitats hangs in the balance.
A Call for Protection
As awareness of the Lost City’s significance and vulnerability spreads, there is a growing movement to protect this underwater marvel.
Scientists and environmental advocates are calling for the Lost City to be designated as a World Heritage site, a status that would recognize its outstanding universal value and help to safeguard it from the threats of mining and other human activities.
By protecting the Lost City, we preserve a unique and valuable ecosystem and ensure that future generations will have the opportunity to study and marvel at this extraordinary place.
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Nancy Maffia
Nancy received a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.