Miles below the turbulent surface of the ocean, enormous cauldrons up to sixty feet tall churn carbon and sulfur at temperatures exceeding 400 degrees Celsius (752 degrees Fahrenheit). The surrounding seawater, at only two degrees Centigrade (35.6 degrees Fahrenheit), compresses and liquefies hydrothermal gases, creating pressures as high as 4000 pounds per square inch (enough to crush a soccer ball to the size of a baseball). Yet, even at such extreme conditions, life exists. An enormous biodiversity thrives on the toxic effluence of the hydrothermal vents. At the bottom of the sea, giant tubeworms, rat-tail fish, clams, various crabs, shrimp, lobsters and ancient creatures form complex communities.
First discovered in the 1970s, hydrothermal vents have become widely known to science as biological hot spots, the rainforests of the deep sea. An individual vent could supply enough energy to support millions of multi-cellular creatures. Because of the discovery of simple bacteria in and around the vents themselves, scientists have proposed that these environments fostered the evolution of the first life forms on Earth.
According to recent genetic studies, the simplest organisms need only 256 genes to produce the enzymes necessary for cellular processes. And the most complex chemicals in these primitive cells could have been formed in geothermal reactions at the bottom of the ocean four billion years ago. Amino acids, the building blocks of proteins and DNA, could have been assembled naturally below the planet’s crust. The products would then be ejected into the frigid waters of the deep, where cooler temperatures and the incidence of clay minerals would have aided the formation of the building blocks of the first cells.
If this was the case, the search for extraterrestrial life (even within our own solar system) would become more promising than ever before. Astrobiologists have proposed the existence of hydrothermal vents in Mars’s ancient oceans. Europa, Jupiter’s icy moon, could harbor oceans below a fifty-mile-thick sheet of pack ice. The presence of faults along its glacial surface suggests the occurrence of significant seismic activity, which generates the formation of deep-sea vents. The biodiversity of Earth’s hydrothermal vents indicates that life could thrive at the bottom of Europa’s liquid oceans. Who knows? Since life seems to exist wherever water and energy exists, countless worlds could harbor organisms similar – yet radically different – to Earth’s. The hydrothermal vent, a potential birthplace for life on Earth, could be the gateway to the evolution of life elsewhere in the universe.