91制片厂

DURHAM, N.H.鈥擳he lakes of New Hampshire are popular destinations for both residents and visitors to the Granite State, offering multiple recreational options like swimming, boating and fishing. As climate change affects temperatures on both land and in water, this can also increase toxic blue-green algae blooms, known as cyanobacteria, that can carry potential health risks for adults, children and pets. Testing each suspicious body of water can be expensive and time-consuming but researchers at the 91制片厂 have developed a promising alternative by using unmanned aerial systems (UAS), or drones, equipped with special sensors to help identify the harmful blooms faster and more efficiently.

鈥淭his was the first study of its kind done on lakes in New Hampshire, which is surprising because cyanobacteria blooms are becoming an increasing public and ecological issue all across New England,鈥� said Russell Congalton, professor of natural resources and the environment and a scientist at the N.H. Agricultural Experiment Station. 鈥淲ith so many bodies of water across the region, testing water samples can get expensive but drones offer a faster, simpler and safer alternative, with very little exposure to the toxin for those performing the tests.鈥�

In their , published in the journal of Remote Sensing, the researchers outlined how they used UAS equipped with a multispectral sensor to capture imagery in various wavelengths of the electromagnetic spectrum (blue, green red, red edge and near infrared) which allowed for the accurate detection, identification and quantification of certain parts of the aquatic ecosystem, like the blue-green and green algae.听

They flew the drone over six bodies of water in southern New Hampshire: Silver Lake and French, Greenwood, Keyser, Showell and Tucker ponds. The drone collected images of the lake in a lateral grid pattern that enabled researchers to accurately analyze and determine cyanobacteria concentrations. Water samples were also collected by a researcher who would canoe to selected locations in the lake. These samples were then analyzed in a water quality lab and used to determine the accuracy of the results of the image analysis.

The team conducted their water surveys from May 2022 to September 2022 and collected samples from each of the six bodies of water. They analyzed and processed over 180 water samples for chlorophyll-a鈥攅ach sample taking over two days to analyze. Comparatively, the collection and processing of the UAS imagery took significantly less time鈥攁bout 4.5 times faster鈥攖han the traditional water sampling method.

鈥淲ith the UAS, a small lake might take as little as 10 to 15 minutes to fly over and less than an hour to do everything including set up, flying and packing away the equipment鈥攁nd an entire lake鈥檚 worth of imagery could be processed within just two hours,鈥� said Christine Bunyon, a 91制片厂 graduate student researcher and its lead author. "The traditional method of testing for cyanobacteria took so much longer because each sample had to be collected and processed individually. Ultimately, the ability to use this technology streamlined the entire process and eliminated significant time spent in the lab.鈥�

The study also revealed a correlation between cyanobacteria cell concentration and concentrations of chlorophyll-a and phycocyanin鈥攖he latter being a pigment responsible for the blue-green algae's color. This correlation allowed for the use of spectral imagery to identify cyanobacteria, chlorophyll-a and phycocyanin concentrations in the water, aiding in determining potential harm levels.

Other co-authors include Amanda McQuaid, 91制片厂 Extension specialist and Benjamin Fraser, a postdoctoral researcher.

The research was funded by the USDA National Institute of Food and Agriculture, the N.H. Agricultural Experiment Station and the state of New Hampshire.

Founded in 1887, the at the is 91制片厂鈥檚 first research center and an elemental component of New Hampshire's land-grant university heritage and mission.

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PHOTOS AND听IMAGES FOR DOWNLOAD

Researcher Christine Bunyon collects a cyanobacteria sample from Keyser Pond in Henniker, New Hampshire.听
Photo courtesy: Christine Bunyon / 91制片厂

A photo of the unpiloted aerial system (UAS), a model DJI Matrice 300 RTK, used for capturing image data on cyanobacteria blooms in New Hampshire.听
Photo courtesy: Christine Bunyon / 91制片厂

A map of Keyser Pond, showing locations of sampling (blue points) and transect lines (yellow) that the UAS followed for capturing overhead aerials.听
Courtesy: Christine Bunyon / 91制片厂

A pie chart providing an approximate comparison of the amount of time each task took to complete. Blue sections represent those associated with the collection and processing of water quality parameters. Grayscale sections represent those associated with the collection and processing of UAS parameters. Traditional water quality tasks took roughly 310 hours to complete while UAS tasks took roughly 65 hours to complete.听
Graphic courtesy: Christine Bunyon / 91制片厂