Deepest cold seep

First discovered in the Gulf of Mexico in 1983, cold seeps are an ocean-floor biome sustained by methane and sulphide rich fluids seeping from the seabed. They sometimes contain brine pools of super saline dense water in shallow depressions. Tubeworms living in cold seeps are believed to live for up to 250 years. The deepest yet discovered is at a depth of 7,434 m (24,389 ft) in the Japan Trench off the coast of Japan in the Pacific Ocean.

Cold-seep communities rely on the chemical energy produced by bacteria feeding on the escaping fluids and forming bacterial mats, which then attract animals including species of mussels and clams not found elsewhere.