Hydrothermal Vents: Introduction

What are hydrothermal vents?
Hydrothermal vents are spectacular, dynamic features of the seafloor, and lie 100's to 1000's of meters deep. Hydrothermal vents are underwater geysers that gush super-hot (up to 360ºC or 680ºF), mineral-rich water, and support a diverse community of organisms. The cooler waters, below 115ºC, on the seafloor and along the walls of the chimneys, support an abundance of flora and fauna. This ecosystem is supported by microbes, whose energy is generated by chemical energy from the fluids from the hydrothermal vents (chemosynthesis).

When and where were the vents discovered?
They were discovered in 1977 in the Pacific Ocean. Since then they have been found in the Atlantic, Indian and most recently, the Arctic Ocean. Most vents occur at an average depth of 2,100 meters (7,000 ft) along the Mid-Ocean Ridge system - an underwater mountain chain that winds around the globe.

How do the vents form?
Hydrothermal vents form in areas of volcanic activity where tectonic plates are moving apart, at divergent plate boundaries. Cold sea water seeps into the Earth's crust where it is heated by the underlying molten lava. This hot fluid then rises to the surface where it emerges through the seafloor as buoyant plumes of particle-rich, superheated fluid.

Click on the words and numbers below to find out more about hydrothermal vents.
(courtesy of Woods Hole Oceanographic Institute)