black smoker

Hot waters emanating from hydrothermal vents are less dense than seawater and rise up above the volcano into the water above as a plume. Similar to smoke coming from a smoke stack, the hot waters rise, expand, and drift in the current like smoke in the wind. Much like smoke plumes dispersing into air, as the water rises up it pulls in surrounding seawater, diluting the hydrothermal water. Within ten minutes or so the hot water has risen anywhere from 100 to 250 meters or more above the volcano and has pulled in almost 10,000 times its volume in surrounding seawater, expanding the hydrothermal waters into a large cloud or plume. The 10,000 times dilution has almost eliminated any temperature difference between the plume and the surrounding deep ocean waters. Image courtesy of NASA.

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