Nitrogen Fixation by <i>Gloeocapsa</i>

Abstract

The continuous growth in a medium free of combined nitrogen and the experimental production of ethylene via acetylene reduction indicate that nitrogen fixation by blue-green algae is not solely confined to filamentous genera with heterocysts. Axenic cultures of Gloeocapsa sp., adapted to nitrate-free medium, form ethylene at rates comparable to those of species known to fix nitrogen.