Sergei Nikolaevitch Winogradsky (1856–1953), a Russian-born microbiologist who worked in France for most of his life; his investigations on nitrification and colourless sulfur bacteria led him to the discovery of the chemolithotrophic mode of life; his studies on the bacteria involved in the biogeochemical cycles of nitrogen, sulfur and iron and of soil microorganisms made him one of the founders of the science of microbial ecology.