Warning Light
Water quality researchers study the fluorescence of freshwater algae as a biological alarm system

Second-year graduate student Jamie Pinto, left, leads a team of undergraduate researchers at the Sen. George J. Mitchell Center for Environmental and Watershed Research, where the focus is on cultivating strains of algae species.  Working with Pinto are, left to right, Sarah Sturgell, Whittney Varney, Jordan Duncan and Amanda Maloney.  Internationally recognized for its leadership in water quality research, the Mitchell Center is a critical resource for researchers who study Maine's water resources.   Links related to this story

Tireless, inconspicuous and keenly aware, they are perhaps the perfect sentries: free-floating algae that are extremely sensitive to their environment, reacting in predictable ways to any toxins that invade their aquatic homes. A team of University of Maine scientists is working to harness the natural sensitivity of these primitive plants, with the goal of ensuring a safe supply of drinking water for all.

Ubiquitous and lightly tinged with green, freshwater algae species with unwieldy names like Ankistrodesmus falcatus may soon serve in the same capacity as the proverbial canary in the coal mine, providing a biological alarm system that warns of potential threats to human health.

"In nature, algae fluoresce and give off light," says John Peckenham, assistant director of the Sen. George J. Mitchell Center for Environmental and Watershed Research at UMaine. "Toxins have a clear effect on how algae fluoresce. After the attacks of 9-11, we began to look for ways to use this behavior as a monitoring device to help ensure the security of our drinking water."

Combining the Mitchell Center's extensive expertise in environmental monitoring and water quality with UMaine chemistry professor Howard Patterson's experience with the molecular properties of fluorescence, Peckenham built a multifaceted team that includes bio-optical oceanographer Collin Roesler of the Bigelow Laboratory for Ocean Sciences and a highly skilled core of graduate and undergraduate researchers.

With more than $400,000 in funding from the federal Environmental Protection Agency's homeland security research programs, the team is in the midst of developing an algae-based sensor system that can be easily integrated into the existing monitoring networks of public water supplies.

"The Department of Homeland Security is obviously concerned about drinking water safety and the security of our water resources, both with regard to accidental contamination and terror threats," says Patterson.

"The idea is to devise a network of sensors that can monitor the algae population in our lakes, ponds and reservoirs, and tell us if the water is okay to drink."

One of the project's key researchers is Jamie Pinto, a graduate student in UMaine's Ecology and Environmental Science Program. After overcoming the challenges of establishing pure algae cultures in the lab, Pinto began the daunting task of quantifying the algae's relative responses to toxins. The tiny plants react in distinctly different ways to various contaminants, making them uniquely valuable for water quality monitoring.

"Algae are particularly useful because of their rapid response to environmental changes," says Pinto. "Toxic contaminants introduced to water supplies cause changes in algae chlorophyll chemistry, which can be monitored using fluorescence technology or sensors. We are working to determine how different toxins affect algae fluorescence intensity and if these effects are similar for different types of algae and different types of toxins — how they change with stress as a function of the stressor."

Once a baseline response is established for each potential toxin, the associated fluorescence levels for the algae become a computer-based standard against which sensor data can be immediately evaluated. Working around-the-clock, a sensor array installed in a public water supply could rapidly locate and identify a contaminant by measuring its fluorescent signature in the pond's native algae population against a database of known signatures at the local water company.

Working with Collin Roesler of Bigelow and Andy Thomas from UMaine's School of Marine Sciences, graduate student Chris Proctor is conducting experiments with an in-situ sensor in water supply lakes. New technology will be built around the device.

To ensure that the new monitoring technology being developed will transition smoothly into commercial use, Peckenham also enlisted the help of Sewell Engineering Co., in Old Town, Maine. Experienced with monitoring systems, as well as GIS systems and mapping, the company was a perfect fit for the project. It will assist with the logistics of maintaining both the sensors and the fluorescence library in a way that is efficient and reliable enough for commercial use.

By installing an array of sensors in the water supply, the system allows utilities to more accurately isolate the source of contamination and helps to avoid false alarms. According to Peckenham, water companies are interested in the technology not only because it can be easily integrated into existing systems, but also because the sensors can monitor the algae population.

Roesler has developed a way to distinguish between different species of algae based on their fluorescence, providing water companies an early warning system for algal blooms and other imbalances in the water supply.

"Making sure that this technology gets put to use is critical," says Peckenham. "The real goal here is to develop a new technology that we can take to market as a security system."

The project's emphasis on the reliability of the system is revealed in the methods used for examining the algae. While Pinto cultures pure strains of certain species in the lab, doctoral student Lucner Charlestra is in the field, applying cutting-edge sampling techniques to make sure that the project is based on an accurate assessment of the native algae populations.

The relative fluorescence of samples Charlestra has collected from area water supplies are quantified along with the laboratory cultures, providing a more realistic picture of what can be expected in the field.

The project promises to improve both the security and management of public water supplies. It already is proving to be an outstanding model for collaboration in addressing environmental concerns.

"The real beauty of it is that this system can protect our water by responding not just to one or two kinds of toxins, like most tests, but also to any toxin that enters the water supply," Peckenham says.

by David Munson
March-April, 2007

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