The Lost City of Hydrothermal Vents

A black smoker hydrothermal vent. (source: Schmidt Ocean Institute.)

Post Author - J. Carlin Decker III

Life can be just as simple as it is complex. There is a lot of credit to be given to simple, microbial organisms such as the undersea ecosystems that are often claimed to be the origin of life on Earth. Heat and minerals spewing from the Earth’s core have supported the growth of bacteria and other microorganisms for billions of years as evidenced in the fossil record, and from these microbes many thriving seafloor communities have blossomed throughout our planet's history. Recently, scientists have studied new minerals from a famous hydrothermal vent region in the mid-Atlantic which has led to new avenues for developing this undersea origin theory. 

When discovered in December 2000 on a National Science Foundation expedition, the ‘Lost City’ hydrothermal vent field was found to operate differently from vents previously observed. Hydrothermal vents, like those discovered in the Pacific, have been observed to shoot out extremely hot, black, cloudy sulfide as seawater reacts to magma chambers below the seafloor, earning themselves the nickname ‘black smokers.’

Hydrothermal vent diagram 

The vents in the Lost City, however, are made up completely of carbonate, significantly taller, the temperature hot, but not as extreme, and formed differently. Seawater mixes with the mantle rock in a process called serpentinization, in which towering, undersea spires are able to form, some being as tall as 18 stories! The Lost City sits right next to the mid-Atlantic volcano ridge, and the tectonic shifting in the area creates vents that connect directly to the mantle. The alkaline pH levels, unique temperatures, and concentrated carbon create the conditions for such unique vent formations.

Recently, a team of marine excavators were able to actually recover quite a bit of specimen material from the Lost City. Over a thousand meters worth of mantle peridotite was collected in an expedition to Atlantis Massif, the undersea mountain that the Lost City sits on, that departed in Spring 2023. The material is being inventoried and analyzed to understand the composition and structural context of the minerals. The findings could have major insight on the formation of undersea volcanoes and seafloor magma flow. There has been a debate amongst scientific disciplines as to where the origins of life actually occurred on Earth, but the team here hopes to dig deeper into the oceanic origin theories.