With temperatures close to the melting point of aluminum and depths reaching as far down as 16,000 feet, you wouldn't believe that these vents are actually a beacon for life on the ocean floor. However, you'd be surprised to learn that the exact opposite is true. Surveys of biological life on the ocean floor put the density of organisms found near hydrothermal vents as high as 100,000 times greater than that of the surrounding regions. This is strange because such harsh conditions would normally prove difficult for most marine organisms to survive in, much less thrive, but the life around hydrothermal vents is by no means normal.
The majority of life at these depths rely upon "marine snow", or sinking organic matter, to survive, but the organisms that call hydrothermal vents home are not like the majority of life on the ocean floor. It all starts in the same place as most food chains, very small, in the form of bacteria that feed off of sulfur compounds, which, as was mentioned before, is the primary constituent of the product of hydrothermal vents. These bacteria in turn attract other small organisms like copepods which themselves bring in various types of predators ranging from crustaceans to fish and octopuses.
The most important role in the vent ecosystem is played by the tube worms which, because of their nature of directly absorbing the surrounding nutrients into their tissues, provide bacteria with a rich environment to coexist with the tube worms. This symbiotic relationship helps to maintain a stable ecosystem which has gone on to foster a number of profound developments.
A particular organism which has cemented the importance of studying hydrothermal vents is a species of bacteria which photosynthesizes not from the light of the Sun, but from that of these hydrothermal vents. This is the first organism to ever be seen to exhibit this trait.