Spirulina

Spirulina is the dried biomass of free-floating, filamentous cyanobacteria, chiefly the species Arthrospira platensis and Arthrospira maxima, whose cylindrical, multicellular filaments form an open, left-handed helix. It grows naturally in tropical and subtropical lakes with high pH and high concentrations of carbonate and bicarbonate; Arthrospira platensis occurs across Africa, Asia, and South America, while Arthrospira maxima is limited to Central America. The Aztecs harvested it from Lake Texcoco as a food source they called tecuitlatl, and today it is cultivated, mostly in open-channel raceway ponds stirred by paddle wheels at around pH 8.5 and thirty degrees Celsius, for use as a human dietary supplement and whole food and as a feed supplement in aquaculture, aquariums, and poultry.