Karl Otto Stetter (born 16 July 1941) is a German microbiologist and authority on astrobiology. Stetter is an expert on microbial life at high temperatures.
The majority of Stetter's research has focused on sampling, isolating and characterizing archaeal organisms which comprise the third domain of life, particularly undiscovered extremely heat-loving (hyperthermophilic) bacteria and Archaea, also called extremophiles, growing optimally between 80 and 113 °C.
Nanoarchaeum equitans, an archaeal microorganism containing the world's smallest known genome, was discovered by Stetter in 2002 in a hydrothermal vent off the coast of Iceland. This archaebacterium was described in the scientific journal Nature in May 2002.[2]
^Fiala, Gerhard; Stetter, Karl O. (June 1986). "Pyrococcus furiosus sp. nov. represents a novel genus of marine heterotrophic archaebacteria growing optimally at 100°C". Archives of Microbiology. 145 (1): 56–61. doi:10.1007/BF00413027. S2CID41589578.