An underwater CO2 geyser
At a depth of 1,604 meters on the Northwest Eifuku seamount, a submarine volcano in the Pacific, scientists found a hydrothermal field with an unusual output. Discovered in April 2004 by a team from the National Oceanic and Atmospheric Administration (NOAA), the site was named the Champagne Vent. The name comes from the visible streams of buoyant, milky droplets rising from the seafloor, which look like bubbles in a champagne glass.
These droplets are nearly pure liquid carbon dioxide. The immense pressure at this depth—nearly 160 times that of the surface—keeps the CO2 in its liquid state. This is one of only two known locations on Earth where liquid CO2 is actively venting from the seafloor. The fluid emerging from the small, white chimneys has a temperature of 103°C (217°F), while the liquid CO2 droplets themselves are much cooler. Analysis of the hot vent fluid revealed a CO2 concentration of 2.3 moles per kilogram of water, an order of magnitude higher than any previously reported values from hydrothermal vents.
A natural laboratory for ocean acidification
The Champagne Vent is an environment to study the effects of high CO2 levels in marine ecosystems. The constant release of carbon dioxide significantly lowers the pH of the surrounding water, making it far more acidic than typical seawater. This creates a natural experimental site that simulates the conditions predicted for future global ocean acidification driven by climate change.
Despite the extreme chemistry, a specialized biological community exists here. While the areas of most intense venting have few animals, the surrounding seafloor has dense colonies of mussels, some reaching 18 cm (7 inches) in length and piled several layers deep. These mussels, along with shrimp, crabs, and limpets, have adapted to the harsh conditions. The shrimp species Opaepele loihi is particularly abundant. Scientists study these organisms to understand how marine life might adapt to a more acidic ocean. The entire ecosystem is chemosynthetic, deriving energy from chemical reactions rather than sunlight.