How a hydrothermal vent system works

Hydrothermal vents are one of the most spectacular features on the seafloor. They form in places where there is volcanic activity, such as along the Mid-Ocean Ridge. Water seeps down through cracks in the seafloor and is heated by molten rock deep below the ocean crust to as high as 400°C (752°F). The hot fluid rises through the rock and gushes out of the vent openings and surrounding seafloor. This hydrothermal fluid carries with it dissolved metals and other chemicals from deep beneath the ocean floor. (Illustration by Eric S. Taylor, © Woods Hole Oceanographic Institution)