The invasive zebra mussels clog industrial facility pipes. Photo: Dan Minchin Retrieved from Wikimedia Commons
Scientists have identified a new weapon to ward off two troublesome Great Lakes invaders: A bacterium strain that destroys their guts.
It may prove to be an environmentally friendly and effective method of controlling quagga and zebra mussels. Introduced to the lakes in the 1980s, the mussels eat up things like phytoplankton — food that native fish and other life depend upon.
They also clog things like the water intake pipes of power plants. Nowadays they are removed by hand or with the treatment of chemicals that can be harmful to the environment.
A strain of the bacterium, P. flourescens, destroys the bivalves’ digestive systems.
Daniel Molloy, a researcher at the New York State Museum, once helped develop an environmental safe method, using a bacterium, to kill black flies and mosquitoes. He had a hunch that a strain might be found to kill invasive mussels, says Molloy’s colleague Denise Mayer.
And they found it hiding in plain sight.
“[The bacterium] is ubiquitous, you know, common found all over the world. It’s everywhere, it’s on your fingers,” said Mayer, a lead research scientist at the museum which hosts scientists in a variety of areas.
Their research was backed, among others, by the Empire State Electric Energy Research Corporation and the U.S. Department of Energy’s National Energy Technology Laboratory.
“Our intent was really to provide a tool to the … power industry and such, to clean their pipes…to reduce the use of some of the chlorinated compounds,” Mayer said.
The method isn’t designed for open water use so it doesn’t solve the problem of the mussels’ impact on the ecosystem.
Chemicals like chlorine can harm more than just the mussels, Mayer says.
And power industries are interested in getting rid of current methods, she says.
“Some of the biggest supporters, the Department of Energy, you know, power, they want a different method to use,” Mayer said. “So it’s not like they’re out there saying, we don’t care we’ll apply this to the environment. They really … would like to have an alternative.”
Typically the bacterium is associated with plant roots and helps the plant ward off fungi and disease.
But it also contains a chemical that is exclusively harmful to the two mussels and destroys their digestive systems. Other critters tested, like fish and other mussels, are unaffected by it.
The bacterium is a dish best served dead. Live cells could make fish sick, Mayer said.
“The cells are actually dead, so it’s acting like a pill .… it’s giving the mussels something to grab onto.” Mayer said.
The researchers screened more than 700 bacterial strains in search of the one that would do the trick.
“What they were able to do was pretty amazing. It’s more than just a needle in haystack,” said Sarahann Rackl, an Invasive Mussel Project Manager at Marrone Bio Innovations.
The museum then looked for a partner to commercialize the bacterium into a product.
And Marrone Bio Innovations answered the call. The California company focuses on environmentally friendly solutions to pest management. The company and the museum shared a $500,000 award from the National Science Foundation to aid in the bacterium’s development and commercialization. This year the company received another $600,000 from the foundation.
It is expected to be available in March under the name Zequanox.
“We feel that this is another product in the toolbox for people to use,” Rackl said.
“There’s a lot of value and potential value in this product because it’s environmentally selective and benign.”
And the product won’t expose people to harmful chemicals, she says.
And time is money. Chlorine treatments, if done properly can take 7 to 10 days or longer, she says. Zequanox takes six hours.
DTE Energy spends between $100,000 and $500,000 a year controlling mussels in its six Michigan power plants, said Gary Longton, a DTE senior environmental engineering technician. The mussels clog pipes that draw in water to cool equipment.
Right now DTE employs divers to clean pumphouses with the same industrial commercial-grade scrubbers designed to scrape barnacles off of boat hulls. Or the company treats them with chlorine or sodium hypochlorite.
“Detroit Edison knows their business and they have chosen primarily mechanical because it’s the cheapest form, they’re no dumbbells,” said Don Schloesser a research biologist at the U.S. Geological Survey Great Lakes Science Center.
Longton says that the company is always open to new and effective methods to rid itself of the nuisances. He says that salesmen test strips different coatings in the pump houses. Once it was cayenne pepper.
“We’re always open for the magic bullet,” he said.
“If anyone came up with the magic bullet they could be a very rich and famous person,” he said, “and no one has come up with a magic bullet yet.”