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Did you know that there really is a lost city in the ocean? The Lost City hydrothermal vent field is a site of towering white chalk chimneys ranging from 65 to 200 feet tall located in the Atlantic Ocean, several kilometers away from the underwater mountain range known as the Mid-Atlantic ridge. Hydrothermal vents are underwater volcanoes on the seafloor where hot water that travels through the earth’s crust and gets heated, rises up and comes back out through the chimneys as extremely hot fluid, sometimes reaching temperatures over four times hotter than boiling water. The fluids that comes out of most hydrothermal vents are acidic and filled with elements such as iron and sulfur, giving it a smoky black appearance. At lower temperatures, vent fluids are a white-grey color.

<figure class="wp-block-image"><figcaption>Diagram of a hydrothermal vent field, from Wang et al. (2018), https://www.mdpi.com/2075-163X/8/11/512</figcaption></figure>

On the other hand, the carbonate chimneys formed at Lost City are created through different processes and the resultant fluids are alkaline and have different components such as calcium and barium. Lost City hydrothermal fluids also have relatively low temperature, slightly below boiling. The rocks present beneath the seafloor at Lost City are different from those at other hydrothermal vents and they undergo a chemical reaction with the surrounding seawater, creating hydrogen and hydrocarbons, which microbes can use for food. This is essentially a free lunch for the microbes! Researchers study the microbes present at the Lost City as it is a site similar to ocean worlds found on other planets and moons such as Enceladus, which is one of Saturn’s moons, and Europa, one of Jupiter’s moons. The icy oceans present on these moons are hypothesized to support the same water-rock reactions. Therefore, from learning about the microbes present at Lost City, we can potentially learn about extraterrestrial microbes aka alien microbes!

<figure class="wp-block-image"><figcaption>Carbonate chimneys at the Lost City hydrothermal vent field in the Atlantic Ocean, from: https://www.smithsonianmag.com/science-nature/diving-deep-reveal-microbial-mysteries-lost-city-180970234/</figcaption></figure>

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Featured image from: https://www.whoi.edu/know-your-ocean/ocean-topics/seafloor-below/hydrothermal-vents/

Script Author: Shu Ying Wee

Contributing Professor: Dr. Jason Sylvan