Azolla grows free-floating on freshwater. Image from the Ecolink website.

Azolla is a unique freshwater fern that is one of the fastest growing plants on the planet due to its symbiotic relationship with a cyanobacterium (‘blue-green alga’) called anabaena.

Azolla (left) and its endosymbiont Anabaena (right). Image courtesy of the University of Wisconsin’s Department of Botany website.

Anabaena draws down the atmospheric nitrogen that fertilizes azolla, and azolla provides a nitrogen-filled home for anabaena within its leaf cavities. This enables the plant to double its biomass in as little as two days free floating on water as shallow as one inch (2.4 cm).

Azolla’s rapid growth makes it a potentially important sequester of the greenhouse gas carbon dioxide which is converted directly into azolla’s biomass. This provides local livestock feed, biofertilizer, food and biofuel wherever azolla is grown, so that this remarkable plant has the potential to help us weather the Perfect Storm – the related threats of man-made climate change and shortages of food and land as our population passes seven billion.

Read more about why azolla is unique and why it has been called a Superorganism.