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Keep up to speed with our Falkor research cruise with this latest seafloor syntax!

Black smoke billows out of a crusty vent on the ocean floor.
Mineral-laden water emerging from a hydrothermal vent on the Niua underwater volcano in the Lau Basin, southwest Pacific Ocean. As the water cools, minerals precipitate to form tower-like “chimneys.” Image taken during 2016 cruise “Virtual Vents.”  

From June 12 to July 3, the U.S. Geological Survey and Schmidt Ocean Institute will be conducting a research cruise off the coast of Oregon and Washington, hunting deep-sea bubbles and the creatures that eat them. While we post stories about our findings, we’ll also be posting little vignettes like these, in which we serve as your terminology tour-guides to the unusual and hard-to-pronounce words that dwell in the depths of deep-ocean science.

The WaterWord: Hydrothermal Vent


  • If you’ve ever gotten in trouble, then you’re already familiar with the literal meaning of hydrothermal: hot water. A hydrothermal vent, then, is a hot water vent on the ocean floor. They’re caused by magma beneath the Earth’s surface heating water that has seeped into the rocks in the seafloor. The hot water then escapes the rock back into the ocean.


  • Hydrothermal is made up of two ancient Greek words: hydor, meaning “water,” and therme, meaning “heat.” Vent, meanwhile, comes from the French eventer, meaning “to expose to air.”

Use/Significance in the Earth Science Community:

  • Hydrothermal vents are often found near mid-ocean ridges, where two tectonic plates meet and new seafloor  is created. Magma is close to the seafloor there, and the water in seafloor rocks is heated and mixed with mineral-laden fluids.   

  • Hydrothermal vents are of interest to both geologists and biologists.  The hot water contains dissolved minerals dissolved. When the heated water meets the cold overlying seawater, fantastic mineral formations can grow at the seafloor.  The minerals also provide nutrients to organisms that rely on chemicals (instead of photosynthesis) to fuel their metabolism. Methane seeps, which are “cold seeps,” not hydrothermal vents, also host organisms that use chemical processes as a basis for survival.  

U.S. Geological Survey/Schmidt Ocean Institute Use:

  • USGS and SOI are collaborating on a research cruise looking at the ocean floor of the Pacific continental margin off the coast of Oregon and Washington. Although the main focus will be on methane seeps rather than hydrothermal vents, hydrothermal vents do occur nearby at a plate boundary called the Juan de Fuca Ridge.  

  • SOI is no stranger to hydrothermal vents, with many of its research cruises discovering or mapping them. In addition, SOI research projects have delved deep into the very formation of these vents.

  • USGS has published extensively on the mineral formations from hydrothermal vents and the biological communities that can be found near them.

Next WaterWord: Chemoherm

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