Nitrogen-fixing describes the process of transferring atmospheric nitrogen directly into plant tissue. Nitrogen is essential to all living organisms and can be found most abundantly (78%) in the atmosphere. Most plants, however, are unable to absorb di-nitrogen (N2) from the air and depend on microorganisms to turn nitrogen into usable form, which accumulate in the soil and dissolve in water. Plants, such as blue-green algae, which are able to absorb nitrogen directly from the air have an advantage over other plant species in nitrogen-poor waterways and soils.