Blue-green algae, or cyanobacteria, are aquatic organisms that exist naturally in freshwater lakes and ponds but sometimes reproduce rapidly, creating a dense growth called a bloom, which can be toxic, according to Kansas State University.
Cattle deaths have been reported in Kansas this year, and the deaths of seven dogs in three states last year were linked to blue-green algae, the university said.
The problem often shows up in the heat of summer, when a combination of nutrients from farm fields wash into bodies of water, fueling growth of the algae. “This has been a real problem for me the last few years, with few answers,” Kansas State Research & Extension livestock and natural resources agent Jody Holthaus said.
She and extension watershed specialist Will Boyer began searching for more information and reaching out to state agencies, including the Kansas Department of Health & Environment (KDHE), which she knew had been involved in blue-green algae testing in large lakes.
Holthaus helped facilitate a roundtable discussion on the topic last fall with KDHE, the Kansas Veterinary Diagnostic Lab, Kansas watershed specialists, Kansas Department of Agriculture, the Kansas Biological Survey and others.
“We wanted to do some sort of research or demonstration on smaller farm ponds,” Holthaus said. The next step involved setting up a pilot project through a collaboration with KDHE, partnering with Elizabeth Smith, director of the Bureau of Water.
Using previous studies as a starting point, the project involved placing bales of barley straw at least halfway submerged around the edge of ponds known to previously have had blue-green algae, Kansas State said. The earlier work on larger bodies of water indicated that when barley straw decomposes, polyphenols and other chemicals are released that suppress the growth of harmful algal blooms.
Barley straw bales used in the study were located in western Kansas, and a cooperative project was started with Shawnee County Parks & Recreation, the U.S. Army Corps of Engineers and Kansas State Research & Extension. It involves eight privately owned ponds that range from one-half to three acres in size and stretch across Jackson, Jefferson, Nemaha, Shawnee and Greenwood counties.
Holthaus said researchers have found that the compounds resulting from the decomposing barley straw will not kill existing blooms but can suppress the growth of new ones.
KDHE is testing the water in the eight ponds monthly until October to monitor nutrients and other components that contribute to blooms and to learn if water turnover (dilution), the algal species present in the pond and other factors can successfully suppress the algae’s growth.
“So far, the results appear to be promising, but we’ll have to rely on the scientific data analysis to know for sure,” Holthaus said. "Meanwhile, a local producer of barley straw has been located for future study.”
More information about blue-green algae is available on the KDHE Harmful Algal Blooms page.