What Are Hydrothermal Vents?
Hydrothermal vents are places along the seafloor where hydrothermal fluid emerges and mixes with bottom seawater.
How Is Hydrothermal Fluid Produced?
When seawater percolates through fissures, or fractures, in the ocean crust, it is heated to temperatures that can reach well beyond 400°C or 752°F (water can exist as a supercritical fluid at these sites) as it reaches the magma chambers underneath. The hot water then reacts with surrounding rocks, changing its chemical composition in the process. As the water is heated, it then becomes less dense than the cold water and quickly rises, escaping through vents. The acidic hydrothermal fluid, rich in sulfides and other metals that leach from rocks, mixes with the slightly basic bottom seawater. As a result of the two mixing, minerals form these chimneys and plumes or clouds of fine black particles that can be seen in the photos above. These are also known as black smokers.
Why Are Hydrothermal Vents Significant?
One of the reasons why hydrothermal vents are significant is because they are actually homes to remarkable biological communities, such as tube worms seen in the second picture in the first row. They are sites of many unique ecosystems that thrive on chemical energy (from the oxidation of hydrogen sulfide present in the hydrothermal fluid) as opposed to light from the sun.
Also, some researchers say that hydrothermal vents may have been a site for the origin of life. You can read more about that at Science Daily.
Images Credit: 2012 MBARI