The tiny worms, midges and water fleas growing in fish tanks at a university lab represent the invasive organisms that have spread throughout the Great Lakes, often by hitchhiking in the ballast tanks of giant cargo ships.
A few miles down the road on the shores of Lake Superior, colorful pipes and several 50,000-gallon tanks can mimic a ship's ballast water intake and discharge system.
Together, the lab and elaborate piping system are helping researchers figure out the best way to kill invaders before they further damage the lakes' fishery, threaten water quality and cost the regional economy even more money. Ballast water helps stabilize ships in turbulent waters. It's also blamed for carrying invasive species such as zebra mussels and ruffe into areas where they have overwhelmed native species and damaged that environment.
It would be impossible to eradicate invasive species from the Great Lakes, so the goal now is to prevent new exotic species from entering and to stop existing invaders from spreading. The stakes are high: One study released last year put the cost of invasive species to the Great Lakes states at $200 million a year, and there are some invaders — such as a deadly fish virus known as VHS — have yet to hit Lake Superior.
Many in the shipping industry and scientific community think on-board ballast water treatment systems are the answer. The idea is to use chemicals to treat the water a ship has taken up to stay balanced before its cargo is loaded. The treatment's goal is to eliminate as many living organisms as possible before the water is released into the lakes to mix with the native ecosystem. Researchers are determining how many organisms could survive the treatment during a certain timeline.
"The question is how clean is clean? Zero would be great, but is it achievable?" asked Mary Balcer, director of the Lake Superior Research Institute in Superior.
Balcer, her research team and students at the University of Wisconsin-Superior are working toward that goal by analyzing the technology private companies have developed.
The task isn't easy.
A treatment system not only has to kill animals, bacteria and other organisms, but it also has to be easy enough for a shipping crew to operate. And, the water has to be treated in a way that won't harm the lake when it's released.
The treatments — which include everything from ultraviolet light to inaudible sound waves to ozone — are first tested in the lab using the animals growing in the fish tanks. After the treatment is applied, researchers count how many of the organisms survived.
Last month, researcher Tom Markee and several students prepared tests that used chlorine to treat ballast water. Rather than keeping containers of chlorine on a ship, which could be a hazard, the treatment system produces chlorine by running salt water through an electric current. The chlorine is combined with the water that's pumped into the ballast tanks as the ship unloads cargo. Invasive organisms that might be there are killed before the ship releases the water to take on cargo in another port.
Markee thinks the treatment system will need to be adjusted to work well in different types of water, and he's trying to find the ideal dose of chlorine.
"They've tested it in saltwater and it works fine, but when you get to harbors or a river system, that's when it becomes less effective," Markee said.
While some of the world's ships are already equipped with various treatment systems, most of the systems never have been subjected to scientific tests in a freshwater environment, Balcer said.
She and the other researchers work at the only freshwater testing facility of its kind in the world. The land-based site's pipes, tanks and pumps can simulate a Great Lakes ship, giving researchers a chance to find out whether a treatment system that's proven itself in the ocean will also work in the lakes, Balcer said. If a system succeeds at the facility, researchers would then test working ships, she said.
The facility is part of the Great Ships Initiative — a research program that receives federal money along with contributions from the maritime industry, foundations and states. Researchers expect to have plenty of work to do as government officials begin regulating the ballast water ships release into the Great Lakes, said Allegra Cangelosi, who oversees the initiative.
In recent years, the federal government and private companies have gotten serious about spending more money on research of ballast treatment systems, said Cangelosi, director of environmental projects at the Northeast-Midwest Institute. "We're gaining capacity to get to the answers that we need."
Waiting for federal standard
New rules on how to handle ballast water have either been approved or proposed in most of the Great Lakes states, but Congress hasn't established a federal standard.
The shipping industry wants that standard, and the environmental technology companies developing the treatment systems also want a single benchmark for the number of organisms that are allowed to survive when a ship releases its ballast water, said Steve Fisher, executive director of the American Great Lakes Ports Association.
"The lack of congressional action is actually causing inaction on the part of the industry. They're sitting around fearing that if they do something, it will be the wrong thing," Fisher said.
Environmentalists have blamed both the shipping industry and government regulators for allowing ships to dump untreated ballast water into the lakes for so many years.
The shipping industry is concerned about the cost of retrofitting vessels with the treatment systems. The systems themselves can be expensive, and the retrofit involves taking a ship out of commission.
Henry VanOffelen, a natural resources scientist for the Minnesota Center for Environmental Advocacy, sees hope in a couple of treatment systems that have the potential to meet ballast discharge standards in California, where ships by 2020 will have to treat until no live organisms will be released. None of the Great Lakes states have adopted such strict rules.
Balcer said her research team hasn't yet found any viable treatment system that would kill all the living organisms in a ballast tank, but she's happy with the progress that's been made.
"Everyone's behind getting the problem solved," she said. "Eventually we'll be able to find something that really works."