The Charms of Duckweed

An introduction to the smallest flowering plants
Leopard Frog in Duckweed - Click to see more images.

The family of duckweeds (botanically, the Lemnaceae) are the smallest flowering plants.  These plants grow floating in still or slow-moving fresh water around the globe, except in the coldest regions.  The growth of these high-protein plants can be extremely rapid.  Lemna is one of the best known of this group and has been the subject of much research. 

Researchers are using these plants to study basic plant development, plant biochemistry, photosynthesis, the toxicity of hazardous substances, and much more.  Genetic engineers are cloning duckweed genes and modifying duckweeds to inexpensively produce pharmaceuticals.  Environmental scientists are using duckweeds to remove unwanted substances from water.  Aquaculturalists find them an inexpensive feed source for fish farming.  [ More topics ]

To learn more about these fascinating plants, next read the botanical facts, or view some duckweed illustrations.  Read about cloning.

Topical items:
Duckweed spreads across Lake Maracaibo, Venezuela

Venezuela struggles to remove aquatic plant faster than it spreads over nation's largest lake

Thursday, 17 June 2004
By Alexandra Olson, Associated Press

CARACAS, Venezuela — Efforts to remove an aquatic weed from Venezuela's largest lake are barely keeping up with its growth, the environment minister said Wednesday.  The green plant, known as duckweed or lemna, covers about 12 percent of Lake Maracaibo's 13,500-square kilometer (5,400-square mile) surface, said Ana Elisa Osorio.  The lake in western Venezuela is one of South America's largest bodies of water and is an important oil-producing region....
[ read more ]

A later reports (September 2004) indicated that 75% of the duckweed on Lake Maracaibo that year was removed by a government project using mechanical skimmers.  [ read more ]

NASA Image

Above:  NASA image of Lake Maracaibos.  Duckweed (Lemna obscura) can be seen in large swirls across the lake surface.
[ NASA article ] [ high resolution image ]
It is not yet known if this massive growth of duckweed was a one-time occurrence, or if it might recur periodically.  Only time will tell.
More Topics:
[ Why do duckweeds have roots? ]  [ Duckweed Habitat ] [ How to Grow Duckweeds ] [ How to control excess duckweed ] [ Biotech Products from Duckweed ]  [ Herbivores and Pathogens ]  [ duckweed books ]
Rowing through duckweed on the Schuylkill River.
Philadelphia Inquirer Photo, 08/17/1999		 Read how duckweeds can take over lakes and rivers.

Left:  Duckweeds do not normally grow in rivers, but a drought in the summer of 1999 reduced the flow of water into the Schuylkill River in Philadelphia, Pennsylvania.  The reduced flow increased the levels of nutrients and allowed a duckweed bloom to accumulate in the channel.  After this picture was taken, the duckweeds gradually were washed away by the current of the river.
Notes to students and teachers:
  • If you have performed or sponsored a successful science project or class demonstration using duckweeds, please let me know about it.  I am interested in publishing selected projects on this web site.
  • Please report errors, typos or omissions.  I want to make this site as accurate and helpful as I can.  If you have suggestions for additions or changes in organization, they are also welcome.
  • Selected by the sciLINKS program, a service of National Science Teachers Association. Copyright 2001.
  • Books on duckweeds and other aquatic plants are available.
Selected by the sciLINKS program

 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Revised:  September 6, 2008