''Azolla pinnata'' is a species of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except ...

known by several common names, including mosquitofern, feathered mosquitofern and water velvet. It is native to much of Africa, Asia (

Brunei Darussalam Brunei ( , ), formally Brunei Darussalam ( ms, Negara Brunei Darussalam, Jawi: , ), is a country located on the north coast of the island of Borneo in Southeast Asia. Apart from its South China Sea coast, it is completely surrounded by the ...

, China,

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

, Japan,

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republi ...

, and the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

) and parts of Australia. It is an

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments ( saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

, it is found floating upon the surface of the water. It grows in quiet and slow-moving water bodies because swift currents and waves break up the plant.Pacific Island Ecosystems at Risk
/ref> At maximum growth rate, it can double its biomass in 1.9 days, with most strains attaining such growth within a week under optimal conditions. ''A''. ''pinnata'' is a small fern with a triangular stem measuring up to 2.5 centimeters in length that floats on the water. The stem bears many rounded or angular overlapping leaves each 1 or 2 millimeters long. They are green, blue-green, or dark red in color and coated in tiny hairs, giving them a velvety appearance. The hairs make the top surface of the leaf water-repellent, keeping the plant afloat even after being pushed under. A water body may be coated in a dense layer of the plants, which form a velvety mat that crowds out other plants. The hairlike roots extend out into the water. The leaves contain the cyanobacterium '' Anabaena azollae'', which is a

symbiont Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or paras ...

that fixes

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seve ...

from the atmosphere that the fern can use.Sood, A., et al. (2005). Indicators of phosphorus deficiency in ''Azolla pinnata'' (Salviniales, Pteridophyta). ''Acta Botanica Hungarica'' 47:1-2 197. This gives the fern the ability to grow in habitats that are low in nitrogen. The plant reproduces vegetatively when branches break off the main axis, or sexually when sporocarps on the leaves release spores.''Azolla pinnata''.
Nonindigenous Aquatic Species. USGS It is present in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived the ...

and an

invasive weed An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

that has crowded out a native relative, '' Azolla rubra''. It is a pest of waterways because its dense mats reduce oxygen in the water.''Azolla pinnata''.
Idaho Agriculture. The

weevil Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, ...

Stenopelmus rufinasus ''Stenopelmus'' is a genus of marsh weevils in the beetle family Brachyceridae Brachyceridae is a family of weevils. There are at least 150 genera in Brachyceridae. It was treated as a subfamily of Curculionidae. Cladogram A cladogram ( ...

'' is used as an agent of

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also i ...

to manage '' Azolla filiculoides'', and it has been found to attack ''A. pinnata'' as well.Pemberton, R. W. and J. M. Bodle. (2009)
Native North American Azolla Weevil, ''Stenopelmus rufinasus'' (Coleoptera: Curculionidae), uses the invasive old world ''Azolla pinnata'' as a host plant.
''Florida Entomologist'' 92:1 153. Rice farmers sometimes keep this plant in their paddies because it generates valuable nitrogen via its symbiotic cyanobacteria. The plant can be grown in wet soil and then plowed under, generating a good amount of nitrogen-rich

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

.Kaur, H
Biomass production of ''Azolla pinnata'' R. Br. in contaminated soils of Punjab (India).
/ref> The plant has the ability to absorb a certain amount of heavy metal pollution, such as

lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...

, from contaminated water.Jain, S. K. (1990).''Azolla pinnata'' R.Br. and ''Lemna minor'' L. for removal of lead and zinc from polluted water. ''Water Research 24:2 177-83. It is 25-30% protein and can be added to

chicken feed Poultry feed is food for farm poultry, including chickens, ducks, geese and other domestic birds. Before the twentieth century, poultry were mostly kept on general farms, and foraged for much of their feed, eating insects, grain spilled by cattl ...

.Basak, B., et al. (2002)
Azolla (''Azolla pinnata'') as a feed ingredient in broiler ration.
''International Journal of Poultry Science'' 1:1 29.Alalade, O. A. and E. A. Iyayi. (2006)
Chemical composition and the feeding value of azolla (''Azolla pinnata'') meal for egg-type chicks.
''International Journal of Poultry Science'' 5:2 137.

Applications in environmental studies

Recent studies show the usefulness of ''Azolla pinnata'' in the remediation of environmental pollutants. There are two main methods for utilising ''A. pinnata'' to clean up environmental pollutants. The first method is by

adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which ...

, which required the ''A. pinnata'' fronds to be processed into powder and agitated with the wastewater for a fixed duration. The pollutant will adhere to the organic functional groups on the surface of the ''A. pinnata'' powder. In adsorption studies, ''A. pinnata'' was reported in the remediation of dye wastewater containing

methyl violet 2B In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...

, malachite green, rhodamine B, acid red 88 and acid blue 25. The second remediation method is phytoremediation, where living ''A. pinnata'' is suspended on the surface of the wastewater. ''A. pinnata'' was primarily studied due to its high tolerance to environmental pollutants, and ability to hyperaccumulate heavy metals. Phytoremediation of industrial wastewater containing heavy metals (such as zinc, lead, chromium, mercury, cadmium, copper, arsenic) as well as organic dyes such as

and malachite green are reported in literature. ''A.pinnata'' is also reported to be useful for treating the wastewater (remove nitrogenous waste and phosphorus) of poultry farms.

References

External links

USDA Plants Profile - ''Azolla pinnata''
* {{Taxonbar, from=Q2875199 Salviniales Freshwater plants Ferns of Asia Ferns of Africa Ferns of Australia Nitrogen-fixing crops