Hydrothermal vents are fissures in the ocean floor that leak hot, acidic water.
The size of the opemings range from less than half an inch to more than six feet in diameter. These brines are complex solutions containing lots of elements leached from the rock formations that they have transversed. As they are often black in colour these vents are sometimes also referred to as 'Black Smokers'. These vents are normally found along the crest a of mid ocean ridge, a 46,000 mile long chain of mountains that wraps around the earth. They tend to form in linear zones a few kilometres long by a few hundred metres wide.