Biology major Crutchfield tackles duckweed in senior presentation

Release Date: 6/15/2010

Clarksville, Ark. --- If it walks like a duck and quacks like a duck, it's probably a duck. But what about duckweed?

Taylor Crutchfield conducted her senior biology research on how the common water plant, duckweed, could be used to help purify contaminated water.

Botanically assigned to the Lemnaceae family, duckweed is the smallest flowering plant in the world. But while an individual duckweed plant may measure only a few millimeters in size, interest in the plant is growing, as more scientists seek to unlock the potential of this diminutive plant. As pointed out by John W. Cross in his book The Charms of Duckweed:

Researchers are using these fast-growing 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.

Taylor Crutchfield, a native of Claremore, Okla., spent part of her senior year studying the plant.  Her senior research project explored the potential for using duckweed to help purify contaminated water sources.

“We wanted to try different samples of contaminated water to see how well the duckweed would do in filtering the toxins out of it, as well as how much starch the plant produced,” said Crutchfield. “We used effluent from catfish runoff, soybean, and rice hull, as well as runoff from a swine farm and a synthetic medium.”

She said as a last minute addition they also used ordinary tap water, to see how the duckweed would thrive in that environment. 

“The catfish effluent killed everything,” she said. “It was too rich. But with the others – the swine, the rice hull, and the soybean - the duckweed definitely decreased nitrates and phosphates in the solution.” She said the amount of starch also increased, which she had hoped for.

“It shows the potential for what’s thought of as a nuisance weed to be used not only to help purify our water, but also as a fuel to help save the environment,” she said.

Crutchfield believes that if duckweed-based water purification systems could be made viable on a large scale, they might also be a cheap source of bio-fuel, more profitable and easier to grow and harvest than traditional bio-fuel crops such as corn or sugar cane. Duckweed, she explained, will grow in environments that are unsuitable for other plants; they can adjust to various levels of nitrogen and ammonia; and they can be used to create a floating photogenic surface, shielding bodies of water to prevent algae growth.

Duckweed, botanically of the Lemnaceae family, are the smallest flowering plants in the world. Taylor's research measured how well the plant survived in different samples of contaminated water.*

Crutchfield, who served as Residence Hall Association president and played defender for the Eagles women’s soccer team, says her future plans include the possibility of a year in Americorps – a U.S. federal government public service program in which participants gain life and job skills, such as leadership, teamwork, time-management, and hands-on experience in a field of interest. After that? She says medical school looks like a good option to her. We’re betting she’s right.

* Image courtesy of the USGS (http://nas.er.usgs.gov/taxgroup/plants/docs/spiro_compar.html).