Noguera (Sergei Winogradsky, 1856- 1953), after studying Beggiatoa, determined that it uses inorganic H 2 S as energy source and CO 2 as carbon source. He first put forward the concept of autotroph and its relationship with natural circulation.

Wei Noguera-Ski found that there are some filaments flowing from sulfur mineral springs (rich in H 2 S) at the Shuikou, which are composed of a large number of tsutsugamushi bacteria. He also found that after a period of hunger, sulfur particles in the body would disappear, but after H 2 S was given, sulfur particles appeared again. After several small tests, he speculated that sulfur was oxidized in bacteria, and these oxidation processes were the main energy source of bacteria. Later, because the study of sulfur bacteria interfered with the process, Sergei turned to study nitrifying bacteria.