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What are Cold Seeps and Hydrothermal Vents?

Michael Anissimov
Michael Anissimov
Michael Anissimov
Michael Anissimov

Cold seeps and hydrothermal vents are structures found on the ocean floor that support biomes completely independent of the Sun's energy. Cold seeps slowly release hydrogen sulfide, methane and other hydrocarbon-rich fluids, while hydrothermal vents release geothermally heated water rich with the same dissolved minerals. As the ocean floors are typically 2-3 miles (3.2 - 4.8 km) from the surface, these biomes are completely dark for millions of years. They are also heavily pressurized due to the weight of the water above — hydrothermal vent and cold seep biomes usually have an ambient pressure a couple of hundred times greater than at the surface.

Cold seeps and hydrothermal vents are the only long-term biomes whose primary producers do not depend on photosynthesis. Instead of photosynthetic bacteria or plants forming the backbone of the ecosystem, this function is served by chemotrophic bacteria and archaea, which have close symbiotic relationships to heterotrophic organisms which consume them. In turn, larger organisms — giant tube worms, clams, and shrimp -—can consume these to survive.

Cold seeps may harbor tubeworms that can live up to 250 years.
Cold seeps may harbor tubeworms that can live up to 250 years.

Besides the diverse biota that hydrothermal vents and cold seeps harbor, they also possess interesting geologic features. Hydrothermal vents may include black smokers, geysers ejecting cloudy water at a temperature of 400 °C (752 °F), or white smokers, around the same temperature but ejecting white clouds instead of black. Because the pressure at these depths is so great, the water doesn't boil, and instead stays in liquid phase. As the superheated solutions come into contact with the cold water, minerals quickly precipitate out, creating chimney structures that may grow as tall as 60 m (197 ft) before collapsing.

Cold seeps and hydrothermal vents may be found on the ocean floor.
Cold seeps and hydrothermal vents may be found on the ocean floor.

Cold seeps resemble lakes on the bottom of the ocean. The cold seeps release their fluids in the form of brine, which, being denser than typical water, settles along the bottom. Along the edges of these brine lakes, we observe many thousands of mussels, living off the chemotrophic bacteria that feed on the sulfides and methane that leaks from the cold seeps. Cold seeps, being more stable than hydrothermal vents, harbor some long-lived life forms, including tubeworms that live between 170 and 250 years, the longest of any non-colonial invertebrate known.

Michael Anissimov
Michael Anissimov

Michael is a longtime AllTheScience contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Michael Anissimov
Michael Anissimov

Michael is a longtime AllTheScience contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

Learn more...

Discussion Comments

istria

@ Afterall- It is fascinating how life can form if the conditions are right. A hundred years ago, finding life on our planet that does not rely on the sun would be unheard of. Seeing that these animals formed around a hydrothermal vent is amazing. What I wouldn't give to take a submarine ride to see a deep-sea hydrothermal vent community with my own eyes.

afterall

I'm fascinated by the things in the ocean that we still know so little about. The idea that hydrothermal vent tubeworms can live twice as long, or more, as humans- who would have imagined that even a century ago?

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    • Cold seeps may harbor tubeworms that can live up to 250 years.
      By: Sundowner
      Cold seeps may harbor tubeworms that can live up to 250 years.
    • Cold seeps and hydrothermal vents may be found on the ocean floor.
      By: masa
      Cold seeps and hydrothermal vents may be found on the ocean floor.