Sergei Winogradsky, Ukrainian-Russian microbiologist and ecologist (born 1856)

Sergei Nikolaevich Winogradsky (Russian: Сергей Николаевич Виноградский; Ukrainian: Сергій Миколайович Виноградський; 13 September [O.S. 1 September] 1856 – 24 February 1953), also published under the name Sergius Winogradsky, was a Ukrainian and Russian microbiologist, ecologist and soil scientist who pioneered the cycle-of-life concept. Winogradsky discovered the first known form of lithotrophy during his research with Beggiatoa in 1887. He reported that Beggiatoa oxidized hydrogen sulfide (H₂S) as an energy source and formed intracellular sulfur droplets. This research provided the first example of lithotrophy, but not autotrophy. Born in the capital of present-day Ukraine, his legacy is also celebrated by this nation.

February 25 is the 56th day of the year in the Gregorian calendar; 309 days remain until the end of the year.