The giant tube worm is one of the most conspicuous members of a diverse community that forms around hydrothermal vents. Scientists once thought that no living thing could survive the harsh combination of toxic chemicals, high temperatures, high pressures, and total darkness at these vents. But in 1977, researchers diving in Alvin discovered tube worms and other bizarre organisms thriving at a vent off the Galapagos Islands. Similar communities have since been found at several hundred hot spots around the world. These creatures are like nothing else on Earth.
Vents form where the planets crustal plates are slowly spreading apart and magma is welling up from below to form mountain ranges known as mid-ocean ridges. As cracks form at these spreading centers, seawater seeps a mile or two down into the hot rock. Enriched with minerals leached from the rock, the water heats and rises to the ocean floor to form a vent.
Vents are usually clustered in fields, underwater versions of Yellowstones geyser basins. Individual vent openings typically range from less than a half inch to more than six feet in diameter . Such fields are normally found at a depth of more than a mile. Most have been discovered along the crest of the Mid-Oceanic Ridge, a 46,000-mile-long chain of mountains that wraps around Earth like the seams on a baseball. A few vents have also been found at seamounts, underwater volcanoes that are not located at the intersection of crustal plates.
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2016-02-26
2016-02-26
2016-02-26
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