hydrothermal vent

Crack in the ocean floor, commonly associated with an ocean ridge, through which hot, mineral-rich water flows into the cold ocean water, forming thick clouds of suspended material. The clouds may be dark or light, depending on the mineral content, thus producing ‘white smokers’ or ‘black smokers’. In some cases the water is clear.

Seawater percolating through the sediments and crust is heated by the hot rocks and magma below and then dissolves minerals from the hot rocks. The water gets so hot that its increased buoyancy drives it back out into the ocean via a hydrothermal (‘hot water’) vent. When the water, anywhere from 60°C to over 400°C (kept liquid by the pressure of the ocean above) comes into contact with the frigid sea water, the sudden cooling causes these minerals to precipitate from solution, so forming the suspension. These minerals settle out and crystallize, forming stalagmite-like ‘chimneys’. The chemical-rich water around a smoker gives rise to colonies of primitive bacteria that use the chemicals in the water, rather than the sunlight, for energy. Strange animals that live in such regions include huge tube worms 2 m/6 ft long, giant clams, and species of crab, anemone, and shrimp that are found nowhere else.

In 2003, an organism collected from a ‘black smoker’ hydrothermal vent in the northeastern Pacific Ocean provided a new record for the highest temperature at which life can exist and replicate: 121°C/250°F (extended from the previous record of 113°C/235°F). The organism, named Strain 121, could survive up to 130°C/266°F, but it stopped replicating at that temperature.