Ocean sediment has its own geographical features, such as mountain ranges and even underwater volcanoes that clump together in the depths. And although it is hard to imagine, remote sensing vehicles are helping us to discover the ocean’s secrets. Thanks to this, we know that very close to the seamount, west of the Mid-Atlantic Ridge, rises a Lost City, a shadowy landscape with squally columns weaving through the sediment.
The underwater Lost City
The Lost City, as explorers call it, is more than just a dreamlike landscape covered by rocks carved by nature. It is the longest known submarine hydrothermal system in the world’s oceans, with activity dating back at least 150,000 years.
The ghostly place, completely covered by darkness, was discovered by explorers in 2000 at a depth of more than 700 meters. Thanks to remote vehicle exploration, the researchers came face to face with an underwater hydrothermal paradise. To date, nothing similar has been found in any other oceanic region of the world, and although there may be more sites like this one, for now, it is the only one to which science has access for analysis.
The Lost City is composed of numerous vertical cliffs that wind through the sediment and are covered by deposits with astonishingly diverse vent morphologies. Fluids gushing from the column face have produced clusters of delicate, multi-pointed carbonate growths that extend outward as the fingers of a hand turned upward.
Along a length of at least 200 meters, there are multiple chimneys with pinnacles that reach up to 30 meters in height and that together form a carbonate deposit. The main pinnacle is named Poseidon, in honor of the Greek god of the seas. It is much higher than its sister slopes, reaching up to 60 meters from its base in the marine sediment.
Bubbling gas chimneys
The chimneys of the underwater Lost City spew gases at temperatures above 104ºF. Northeast of the Greek god tower, there is a cliff with brief bursts of activity. During the 150,000 years of Lost City activity, cliffs like this one have been reacting with seawater to spew hydrogen, methane, and other bubbling gases into the ocean.
This is why in the cracks and crevices of the pillars, it is possible to find microbial communities, which is surprising due to the scarcity of oxygen, the perfect scenario for the study of the emergence of life. But a little more conventional life is also present in that corner of the ocean. Despite the extreme conditions, crustaceans, eels, and sea urchins also pile up on the columns of the landscape.
But above all, what has caught most of the attention of scientists is that these hydrothermal vents did not form from atmospheric carbon dioxide, nor did sunlight intervene. Everything in it is carved out by chemical reactions on the deep seafloor, opening up the possibility that life could have arisen in the first place at a site with similar conditions.
Unfortunately, scientists are not the only ones who have set their eyes on the Lost City in the deep sea; natural resource extraction companies are also interested in the energy source that lies there. Consequently, researchers are seeking to make this prehistoric natural laboratory more visible to declare it a World Heritage Site and thus preserve its richness that could help us understand where we came from.
Story originally published in Spanish in Ecoosfera
