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
recognized for its leadership in water quality research, the
Mitchell Center is a critical resource for researchers who study
Maine's water resources.
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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
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
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
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
"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
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