For the past 25 years, scientists have been investigating hot water vents which occur along the ridges that cross the ocean floor. These hydrothermal vents are marked by dramatic plumes of black or white water which look like clouds of smoke. I’m Jim Metzner, and this is the Pulse of the Planet. A hydrothermal vent is a place where some of the heat that’s contained within the earth is released to the surface.
“Cracks form which allow cold ocean sea water to travel down into the crust.”
Ro Kinzler is a research scientist at the American Museum of Natural History.
“If the cracks are deep enough so that this water can get close enough to the source of heat, which might be 2,000 meters down, then the water will heat up. When it heats up, it becomes thermally buoyant’ – meaning it’s really light and it wants to rise. It also becomes chemically reactive. Because it’s hot, it wants to dissolve a lot of things out off the surrounding rock. So the cold water comes down the crack, becomes hot and reactive, starts to rise and starts to strip minerals out of the rocks – becoming transformed from ocean sea water, to hot, mineral rich water.”
And that’s what we observe as plumes of underwater smoke.
“This transformed fluid now has a lot of thermal energy. It’s hot and it wants to rise. It rushes up to the surface. When it sees a crack, it actually vents out, much like Old Faithful in Yellowstone National Park, as an underwater geyser. And it mixes with the ambient, cold ocean sea water. Because it then becomes cooler, it wants to crystallize its dissolved minerals – just like you have a hot cup of coffee, it can take a lot of sugar, when it cools down, the sugar will crystallize out. Same kind of thing. Those minerals will crystallize as tiny, black minerals and appear like black smoke.”
Pulse of the Planet is presented by the National Science Foundation. I’m Jim Metzner.