Thermoplasma is a genus of archaea, a group of single-celled microorganisms distinct from bacteria and eukaryotes. These organisms thrive in extreme environments, particularly in hot, acidic conditions, such as those found in coal mine drainage and hot springs. They lack a cell wall, which allows them to adapt to their harsh surroundings. Thermoplasma species are notable for their unique metabolic processes, which enable them to utilize organic compounds for energy. They play a role in biogeochemical cycles, contributing to the breakdown of organic matter in their ecosystems. Their study helps scientists understand extremophiles and the limits of life on Earth.