December 6, 2005
Scientists Discover New Hydrothermal Vents
SAN FRANCISCO -- Scientists exploring the world's sea floor have discovered new super-hot, mineral-rich geysers belching from the southern Atlantic, Arctic and Indian oceans.
The findings are significant because they show that such hydrothermal vents are a global phenomena, which may help shed light on Earth's geological development and the origins of simple life.Thermal vents teeming with exotic creatures were once thought to exist only in the Pacific "Ring of Fire" because of its high volcanic activity and fast-spreading sea floor. But the discovery of boiling hot springs in the slower-growing Mid-Atlantic Ridge 20 years ago opened new avenues of exploration.
"We're still in the very early stages of exploring the deep ocean," said Peter Rona, a Rutgers University marine geologist who led the original Atlantic expedition, but who had no role in the current discoveries.
Results were being presented Monday at an American Geophysical Union meeting in San Francisco.
The latest deep-sea vents - which spew water heated up to 750 degrees Fahrenheit - were discovered along a submerged volcanic mountain range interconnecting ocean basins.
Venting occurs when cold water seeps into cracks in the sea floor rock, is heated by contact with the Earth's interior and shoots up to meet the frigid ocean water. The newfound undersea geysers are known as "black smokers" because of the soot-colored water they spout.
In April, German scientists studying four active thermal vent fields in the southern Atlantic Ocean found three of the vents created smokestacks - formed when water mixes with metals and gushes out - that were linked to volcanic eruptions.
Three months later, Norwegian scientists plumbing the Arctic Ocean uncovered two vent fields at the Mohns Ridge located between Greenland and Iceland. The larger system contained at least 10 major vents rising up to 33 feet while the smaller field was abundant in shrimp, sea spiders and other creatures.
British oceanographers also witnessed a "megaplume" of dissolved minerals rising more than 4,600 feet above the sea floor from a vent in the Indian Ocean. It's the first such plume to be witnessed outside of the Pacific and scientists are trying to piece together what may have caused this eruptive event.
Large deposits of minerals including iron, copper and zinc are believed to exist in the newly discovered vents. But commercial exploitation thus far has been limited by technology and questions of ownership.
Marine biologists are interested in the underwater vents because of the unique ecosystems that spring up around them. Vent animals live without sunlight and rely instead on chemicals to produce energy.
Scientists have yet to fully examine the creatures in the new ocean hot springs, but they expect to find biodiversity. Previous studies have shown that tubeworms and huge clams reside in the Pacific vent sites, while eyeless shrimp are found only in Atlantic vents.
"It really lends to cool questions about how these organisms might move from vent to vent," said Craig Cary, a marine biologist from the University of Delaware who was not part of the research.
On the Net:
American Geophysical Union: http://www.agu.org