Cyanobacteria and Azolla

摘要: Cyanobacteria (blue-green algae) contribute to the fertility of many agricultural ecosystems, either as free-living organisms or in symbiotic association with water-fern Azolla (Fay, 1983). Several species are also taken directly from nature a food (Jassby, 1988) and, although these natural populations only very local importance, strains genus Spirulina cultivated large open-air ponds several countries (Richmond, 1988). important primary producers freshwater fish-ponds and overall probably most oceans (Carr Wyman, 1986).