20150630 - black smokers

"Black Smokers" by Kathy Svitil

In the frigid depths far beneath the ocean surface, at the ridges where new crust is born, lies a landscape more alien than earthly. Here, strange long-necked barnacles, giant clams, and bizarre worms, their blood-red gills fanned out of bodies like bone-white tubes, clump beside towering spires of mineral. Nearby, sooty black clouds billow out from fissures in the seafloor, and organisms swim by, glowing with their own, otherworldly light.
The setting for this surreal scene is the submarine hydrothermal vents of Earth's mid-ocean spreading ridges. At the mid-ocean ridges, molten rock bubbles up from the mantle to the sea floor and cools to form new oceanic crust. Cold sea water percolates down through the fissures in these ridges, and many types of minerals -- like sulfur, copper, zinc, gold, and iron -- are transferred from the hot, new crust into the water.
 
The water, now rich with dissolved metals, is heated and then gushes back up through the cracks, forming hydrothermal vents. As the hot water -- which can reach temperatures of over 700 degrees Fahrenheit -- escapes from the vents and comes in contact with the near-freezing water of the ocean bottom, the metals quickly rain out of their solution. The result are surging clouds of particle-rich water called "black smokers," which often erupt out of tall chimneys of previously deposited solidified mineral.

http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar2.html
https://en.wikipedia.org/wiki/Hydrothermal_vent