A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water is released. Hydrothermal vents are commonly found in places that are also volcanically active, where hot magma is relatively near the planet's surface, e.g. at mid-ocean ridges. Here is a definition and more information: Hydrothermal vent - Wikipedia, the free encyclopedia ...and here are some pictures of hydrothermal vents from Google, and this an extended description that you might find helpful... A hydrothermal vent is a fissure or opening in the Earth's crust where hot water, minerals, and gases are released from the Earth's mantle into the ocean. These vents are typically found near areas of tectonic activity, such as mid-ocean ridges, where magma rises to the surface and heats the surrounding seawater. Hydrothermal vents can reach temperatures of over 400°C (752°F) and release a variety of chemicals, including hydrogen sulphide, methane, and iron sulphide...
