Oct 23, 2024 08:00:00

Tube worms live beneath the Earth's crust in extremely extreme environments, such as around deep-sea hydrothermal vents.

Hydrothermal vents are fissures in the earth that spew out geothermally heated water, which can reach temperatures of several hundred degrees and contain substances harmful to living organisms, such as heavy metals and hydrogen sulfide. However, even in such extreme environments, living organisms can live, and a survey conducted by the Schmidt Ocean Institute in the East Pacific Ridge reported that organisms such as tube worms were discovered when exploring cavities around deep-sea hydrothermal vents.

Animal life in the shallow subsea crustfloor at deep-sea hydrothermal vents | Nature Communications
https://www.nature.com/articles/s41467-024-52631-9

Ghostly white giant worms appear to be reproducing under the seafloor where tectonic plates meet | Live Science

https://www.livescience.com/animals/ghostly-white-giant-worms-appear-to-be-reproducing-under-the-seafloor-where-tectonic-plates-meet

In areas of active volcanic activity, hydrothermal vents are formed when water seeping through cracks in the seafloor comes into contact with magma and erupts as boiling liquid rich in minerals. Most of the deep sea floor is considered inhospitable to most living things, but around hydrothermal vents there live a group of organisms known as 'extremophiles' that can survive under extremely high temperatures and pressures, feeding on the erupted minerals.

Previous research has confirmed that microorganisms live underground around hydrothermal vents, but the presence of large animals such as tube worms has not been confirmed. In order to observe the organisms lurking under the seafloor of the hydrothermal vent, the research team dropped a remotely operated vehicle (ROV) into a hydrothermal vent about 2,515 meters deep in the eastern Pacific Ocean near the Galapagos Islands. The ROV then used its arm to drill a hole in the seafloor and lifted up a piece of debris, revealing a cavity about 10 cm deep.

In the video below, you can see the ROV actually surveying the seabed.

Supplementary video - YouTube


Not only were the cavities filled with adult tube worms, some of which could reach lengths of up to 50cm, but there were also signs of reproduction taking place there.

The research team stated, 'This is the first time that we have confirmed the presence of animals in small cavities beneath the seafloor of deep-sea hydrothermal vents. Previously, the presence of microorganisms and viruses had been confirmed beneath the seafloor of deep-sea hydrothermal vents, but this is the first time that animals also inhabit them.'

Furthermore, the research team speculates that because the tubeworm larvae were distributed throughout multiple cavities, 'some of them migrated under the seafloor and settled at the hydrothermal vents through cracks leading from the cavities to the surface, while some remained in the cavities and became adults. However, it is not clear how the tubeworm colonies living under the seafloor maintain their ecosystem.