Spreading across the seafloor is a global mountain system that has been formed by plate tectonics, the mid-ocean ridges. They are created wherever tectonic plates drift apart and magma rises between the plates. Along these mid-ocean ridges, hydrothermal vents can be found where heated water discharges from fissures in the seafloor. Through the precipitation of minerals dissolved in the vent fluid, two types of chimney-like structures can be formed: the first of which are black smokers, which emit black clouds of mineral particles, and are hot—about 350°C—as they are close to the magma-chamber below. The others are white smokers, which are only about 50-90°C, and are not directly driven by volcanism but by a geochemical reaction called serpentinization. The particle clouds emitted by these white smokers are white and consist of other minerals. These surreal places in the deep sea are home to amazingly rich ecosystems. Their primary producers are microbes that use chemical energy to produce food through chemosynthesis. The chemical processes in this unique environment are thought to be the origins of life on earth—The first step towards the basic unit of life, a cell, might have been the formation of a vesicle—a barrier that separates the inside from the outside. Researchers were able to show in an experiment that vesicles can self-assemble in such an environment of hot, alkaline seawater. According to a controversial study on Canadian bacteria fossils, they might have done so as early as 4.28 billion years ago, just 400 million years after the formation of Earth.
Sources: Jordan, Sean et al., “Promotion of protocell self-assembly from mixed amphiphiles at the origin of life”, Nature Ecology & Evolution vol. 3, (2019): 1705–1714.
Schopf, J. William et al., “Evidence of Archean life: Stromatolites and microfossils”, Precambrian Research, vol. 158, issues 3–4, (2007): 141-155.