section_path: Concentrations and role in the environment/Oceans/Hydrothermal vents
section_name: Hydrothermal vents
paragraph_text: Hydrothermal vents
  
  Carbon dioxide is also introduced into the oceans through hydrothermal vents. The Champagne hydrothermal vent, found at the Northwest Eifuku volcano in the Mariana Trench, produces almost pure liquid carbon dioxide, one of only two known sites in the world as of 2004, the other being in the Okinawa Trough. The finding of a submarine lake of liquid carbon dioxide in the Okinawa Trough was reported in 2006.