Authors: Man-Yin Tsang, Fumio Inagaki

Below the seafloor are trillions of single-celled microbial life. Marine sediments bury these microorganisms deeper and deeper. Meanwhile, the microorganisms face increasing pressures and temperatures and reduced amounts of food and water. Although they are living in difficult conditions, these microorganisms stay alive and maintain their communities. To date, we know that these microbial communities can survive for millions of years, at 2.5 km below the seafloor, and at temperatures over 100°C. Scientists use multiple approaches to study these fascinating microorganisms.