Oases Under the Sea!
Hydrothermal vents have been compared to oases. That's a good description. Oases are lush areas in a desert based on a water source. In a similar way, a vent is an oasis: it is teeming with life in the middle of the nearly barren ocean floor. A vent spewing microbe- and mineral-rich, super hot water is this oasis' water source.
Vent communities are an ecotone. They are a transition zone between the hot water emerging from the vent and the cold environment of surrounding sea water. Just 15 centimeters (6 in.) laterally away from the vent, the seawater is cold, yet the heat and chemicals rising from it can be measured with powerful thermometers for many miles.
The life forms we see are truly bizarre, and some are very ancient. The vents probably predate life on earth. Scientists believe vents have been around for 3.5 - 4 billion years, and life in them probably began soon thereafter. We saw vents for the first time fewer than 25 years ago, in 1977.
Alien Life Forms!
This headline may have an element of truth. The first creatures to appear at a vent are bacteria that come up with the water, sometimes so densely that the vent looks like a snowblower.
The bacteria form thick mats of various colors that cover the area around the vents.
Some scientists believe the bacteria originally arrived on a meteor from outer space--the panspermia theory--while others contend that life on Earth first formed in an ancient hydrothermal vent some 3.5 - 3.8 billion years ago.
Microbial biospheres? -->
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