World Ocean Census - Extract 16 - Hydrothermal vents

3 May 2010

Deep-sea hydrothermal vents and their associated fauna were first discovered in 1977 along the Galapagos Rift in the eastern Pacific. It is now known that these extraordinary seafloor hot springs are found along the 48,000 kilometers (30,000 miles) of mid-ocean ridges that form Earth’s largest continuous volcanic system.

In vent systems, hydrothermal fluid – originating from seawater seeping through Earth’s crust – re-emerges from the seafloor at temperatures of more than 350°C (662°F). In 2006, Census scientists discovered the hottest hydrothermal vent ever recorded; its temperature was 407°C (765°F), hot enough to melt lead. The fluid that is propelled from the vents contains dissolved metals and sulfur, which precipitate out when the superheated liquid meets the surrounding cold seawater, giving it the appearance of dense black smoke. The precipitated material forms vent chimneys that can reach as high as 20 meters (66 feet). Colonies of unusual marine life such as clams, tube worms and exotic microorganisms cluster around these vents, feeding on the chemical soup spewing from the ocean floor.




Smoky white vent fluide rises out of small sulfur chimneys at the North-west Eifuku volcano in the Marania Arc of the Pacific Ocean. This areawas named the Champagne Vent because bubbles of liquid carbon dioxide were rising out of the seafloor. Courtesy of: Pacific Ring of Fire 2004 Expedition. NOAA Office of Ocean Exploration; Dr. Bob Embley, NOAA PMEL, Chief Scientist.







These Bathymodiolus mussels and an unidentified fish live near hydrothermal vents on the Mid-Atlantic Ridge. Courtesy of: Ricardo Santos.


Text and images reprinted with permission from World Ocean Census: A Global Survey of Marine Life by Darlene Trew Crist, Gail Scowcroft and James M. Harding Jr., Firefly Books, 2009

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