image: A cyanobacterial bloom on the surface of Lake Sunapee, N.H. view more
Credit: Photo by Sam Fey.
Throughout the Northeast, lakes are popular destinations for recreation and often prized locations for second homes. However, as more people are moving to these areas, increases in housing density and other lakeshore development are placing new demands on lake water quality. A team of researchers from Dartmouth, the University of New Hampshire and the Cary Institute of Ecosystem Studies has received a $1.47 million grant from the National Aeronautics and Space Administration (NASA) to study this very issue — how has lake water quality in the Northeast’s temperate forests changed over the past three decades, what factors have influenced these changes and how may such patterns continue in a warmer, wetter and more crowded future?
Using new remote sensing and crowd-sourcing citizen-based technologies, researchers will also develop a method to monitor cyanobacterial blooms in real-time, providing invaluable context for freshwater management.
Cyanobacteria (also known as "blue-green algae") are photosynthetic bacteria found naturally in aquatic ecosystems. Under certain conditions, cyanobacteria can "bloom", forming mass aggregations that rise to the lake surface, reducing water clarity. Toxins associated with some blooms can be deadly to fish and hazardous to humans and other animals, resulting in lake closures. Both decreased water clarity and lake closures disrupt the economy, including the tourism industry and other sectors that rely on clean water.
Environmental scientist David Lutz, a research associate and lecturer in Dartmouth’s Environmental Studies Program, will serve as the principal investigator for the team from Dartmouth, the University of New Hampshire and the Cary Institute of Ecosystem Studies. The interdisciplinary research team has expertise in remote sensing, aquatic ecology, terrestrial ecology, demography and ecosystem science.
"To date, there has been a great deal of research focusing on cyanobacterial blooms in highly productive lakes in the Midwest and southern states, where nutrients such as phosphorus and nitrogen are abundant due to runoff from fertilizer applied to agricultural fields. Much less is known about the recent blooms taking place in the Northeast, where clear-water lakes with lower nutrient concentrations are very valuable, especially as recreational locations and vacation home sites that stimulate nearby economies," explained Lutz.
Under the three-year grant, the researchers will explore how human population growth, altered land use and land cover, climate change and lake-specific factors have affected water quality in approximately 2,000 lakes in N.Y., Vt., N.H. and Maine, especially in forested watersheds, many of which are located within "recreation counties." Satellite data will be used to compile lake-specific data and climate-related data to help examine how weather conditions and lake water temperature play into the mix.
The project will draw on the use of an unmanned aerial system or drone equipped with hyperspectral sensors, which are able to estimate water clarity and identify cyanobacterial blooms. The drone will be flown approximately four times a year around each of three focal lakes in the study: Lake Sunapee, N.H; Lake Auburn, Maine; and Great Pond, Maine. The project plans to utilize the mobile app, "Lake Observer," which will provide members of the public or “citizen scientists,” with the opportunity to take part in this project by recording their lake and water quality observations, including whether a bloom is present not only at one of the three lakes in the study, but at lakes across the Northeast. To engage citizen scientists, the research team will work closely with the Lake Sunapee Protective Association, a long-time partner and with other lake associations and management groups throughout the study region.
Kathleen Weathers, an ecosystem ecologist at the Cary Institute of Ecosystem Studies and a co-principal investigator, helped develop the Lake Observer app. “NASA funding will allow us to tap into the power of both remote sensing and citizen science to better understand, predict and manage cyanobacterial blooms. They are becoming a real problem in the Northeast’s lakes, and citizens, scientists and lake associations are eager to find solutions,” explained Weathers.
“By leveraging the expertise of scientists from the natural and social sciences in collaboration with citizen scientists, this research will investigate the complex set of social, natural and environmental conditions that have and may continue to affect the water quality in our lakes in the Northeast,” added the University of New Hampshire research team members and co-principal investigators.
"I am very excited to tackle the issue of cyanobacterial blooms in low-nutrient lakes in collaboration with this talented team of interdisciplinary researchers," said Kathryn L. Cottingham, professor and chair of the Department of Biological Sciences at Dartmouth, who has studied freshwater lakes for over 25 years and is one of the co-principal investigators of the project. "Our research team comes from diverse backgrounds but has a shared interest in understanding the long-term trends in water clarity and developing models to predict how lakes might change given future scenarios for human development, land-use change and climate."
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Available for comment are David Lutz at david.a.lutz@dartmouth.edu and Kathryn L. Cottingham at kathryn.l.cottingham@dartmouth.edu. In addition, Mark J. Ducey, Kenneth M. Johnson, and Michael W. Palace from the University of New Hampshire, and Kathleen C. Weathers from the Cary Institute of Ecosystem Studies, will serve as co-principal investigators of the project.