Chemosynthesis

Most life on Earth is dependent upon photosynthesis, the process by which plants make energy from sunlight. However, at hydrothermal vents in the deep ocean a unique ecosystem has evolved in the absense of sunlight, and its source of energy is completely different: chemosynthesis. Chemosynthesis is the process by which certain microbes create energy by mediating chemical reactions. So the animals that live around hydrothermal vents make their living from the chemicals coming out of the seafloor in the vent fluids! Because they are a local food source, hydrothermal vents typically have high biomass, in stark contrast to the very sparse distribution of animals outside of vent areas where animals are dependent on food dropping down from above. Chemosynthetic microbes provide the foundation for biological colonization of vents. Chemosynthetic microbes live on or below the seafloor, and even within the bodies of other vent animals as symbionts. Where microbial mat covers the seafloor around vents, grazers such as snails, limpets, and scaleworms eat the mat, and predators come to eat the grazers. Tubeworms flourish in small clumps, waving in the warm fluids. A typical picture of an active hydrothermal vent is therefore one with shimmering warm hydrothermal fluids, tubeworms and many other vent species, all densely clustered around the vent, with white microbial mat material covering the surrounding area.