The term "spirulina" commonly refers to the dried biomass of Arthrospira platensis, which is part of the photosynthetic bacteria encompassing the groups Cyanobacteria and Prochlorophyta. Scientifically, there is a distinction between spirulina and the genus Arthrospira. Dried spirulina consists of 5% water, 24% carbohydrates, 8% fat, and approximately 60% (ranging from 51–71%) protein. A 100g serving of spirulina provides 290 kilocalories and is a rich source of various essential nutrients.