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What is a Hydrothermal Vent?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

In 1977, deep sea submariners from Woods Hole Oceanographic Institution who were surveying the ocean floor came across a startling discovery: a hydrothermal vent, teeming with life. A hydrothermal vent forms when there are cracks in the Earth's surface underwater through which magma and lava can seep. Although scientists had conjectured that hydrothermal vents existed, this discovery confirmed the hypothesis, and revealed that hydrothermal vents played host to a wide range of extremophilic life forms, which thrived in the harsh environment along the ocean floor. Since 1977, a small group of scientists has continued to study these unusual and fantastic interconnected colonies of unique organisms.

The most common location for a hydrothermal vent is along mid ocean ridges, because this is where tectonic plates are separating and forming new sea floor. Intensely cold, highly pressurized water which is close to the freezing point seeps into small cracks, where it comes into contact with extremely hot molten rock. The temperature of the water is rapidly elevated to 750 degrees Fahrenheit (400 degrees Celsius) or more, and jets back out of the crack to form a plume of highly mineralized material. The water of a hydrothermal vent does not actually boil, because the pressure of the ocean elevates the boiling point, but it does carry dissolved minerals, especially sulfides, creating a highly visible geyser. This plume makes a hydrothermal vent much easier to find, once scientists know what they are looking for.

Geysers make hydrothermal vents much easier to find.
Geysers make hydrothermal vents much easier to find.

Many hydrothermal vents create towers of minerals where they come into contact with the intensely cold ocean water, and these piles play host to chemosynthetic bacteria, which rely on the materials in the mineralized plume for energy, rather than sunlight. When scientists were able to prove that chemosynthetic bacteria truly existed, it raised questions about life on Earth and other planets, and suggested that there might be colonies of extremophilic organisms on other places on Earth, or in the solar system in general. That anything lives at all around a hydrothermal vent is amazing: the temperature differences are extreme, and the pressure is immense.

Hydrothermal vents harbor unique ocean life, including tube worms.
Hydrothermal vents harbor unique ocean life, including tube worms.

Larger organisms around the hydrothermal vent in turn prey on the smaller ones, creating a unique web of life deep under the ocean. Some of the larger creatures found at hydrothermal vents include bizarre looking tube worms, which lack digestive systems of their own and rely on symbiotic bacteria to provide their nutrition, and giant clams. The environment around a hydrothermal vent is rich with materials, many of which are also valuable to humans, but it is unlikely that hydrothermal vents will ever be exploited for their resources. In addition to being highly delicate environments, they are also extremely hard to access, and may provide valuable services to the environment. For example, chemosynthetic bacteria are used to help clean up chemical spills, converting dangerous materials like hydrogen sulfide to energy.

Frequently Asked Questions

What is a hydrothermal vent and how does it form?

Hydrothermal vents are common at mid ocean ridges, because it's where tectonic plates are separating and forming new sea.
Hydrothermal vents are common at mid ocean ridges, because it's where tectonic plates are separating and forming new sea.

A hydrothermal vent is a fissure on the seafloor from which geothermally heated water discharges. They typically form at tectonic plate boundaries where volcanic activity is common. Seawater seeps into the Earth's crust, gets heated by magma, becomes mineral-rich, and then rises back to the ocean floor, creating these vents.

What types of ecosystems are found around hydrothermal vents?

Magma can seep through hydrothermal vents.
Magma can seep through hydrothermal vents.

Hydrothermal vents host unique ecosystems with organisms that thrive in extreme conditions. These include chemosynthetic bacteria that convert chemicals from the vent into energy, forming the base of the food web. Giant tube worms, clams, and various species of shrimp and crabs are also common, relying on symbiotic relationships with these bacteria.

How important are hydrothermal vents to ocean life?

Hydrothermal vents are crucial for deep-sea biodiversity, offering oases of life in the nutrient-poor deep ocean. They support complex communities by providing energy through chemosynthesis. According to researchers, vents also play a role in regulating ocean chemistry and may have been cradles for the origin of life on Earth.

Can hydrothermal vents affect global climate?

Yes, hydrothermal vents can impact global climate. They release significant amounts of minerals and heat into the ocean, which can influence ocean circulation patterns. Moreover, they emit methane and carbon dioxide, greenhouse gases that can affect the Earth's atmosphere when they reach the surface, as noted by climate scientists.

What are the differences between black smokers and white smokers?

Black smokers and white smokers are two types of hydrothermal vents distinguished by the color of the material they emit. Black smokers release iron sulfide-rich plumes, giving them a dark color, and are typically hotter. White smokers emit lighter-colored minerals, such as barium, calcium, and silicon, and are usually found at cooler temperatures.

Are hydrothermal vents being explored for human use?

Hydrothermal vents are of interest for several human uses, including mining for precious metals like gold and copper, which are abundant in vent deposits. Additionally, they are studied for biotechnological applications, as vent organisms possess enzymes that can function under extreme conditions, useful in industrial processes.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon156475

How would they mine under all the water pressure?

anon123820

Geologists have been mining these minerals since the 90's.

anon18620

I think that the vents should be mined for the minerals they have.

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    • Geysers make hydrothermal vents much easier to find.
      By: pmphoto
      Geysers make hydrothermal vents much easier to find.
    • Hydrothermal vents harbor unique ocean life, including tube worms.
      By: Sundowner
      Hydrothermal vents harbor unique ocean life, including tube worms.
    • Hydrothermal vents are common at mid ocean ridges, because it's where tectonic plates are separating and forming new sea.
      Hydrothermal vents are common at mid ocean ridges, because it's where tectonic plates are separating and forming new sea.
    • Magma can seep through hydrothermal vents.
      By: kmiragaya
      Magma can seep through hydrothermal vents.