Shedding Light on Blue Green Algae – Hobart and William Smith Colleges \
The HWS Update

Shedding Light on Blue Green Algae

Blue green algae (BGA) and macrophytes (rooted plants) are becoming a toxic problem for those living near the Finger Lakes, but the work of Serena Bradt ’18 and other students in the lab of Professor of Environmental Studies John Halfman is shedding light on the habits of this aquatic plant. In March, the geoscience major with environmental studies and art history minors will present a paper on their work at the Geological Society of America’s Northeastern Section annual meeting.

Bradt’s poster presentation includes work conducted during the past two summers on Owasco Lake and the surrounding streams. She took the samples of nutrients while working aboard the Colleges’ 65-foot research vessel the William Scandling and the pontoon boat, the JB Snow.

To get an aerial view of the spread of BGA, the researchers, in collaboration with Assistant Professor of Physics Ileana Dumitriu, Physics Lab Technician Peter Spacher and students of the Department of Physics, used drone technology. “Serena helped spearhead the field and data analysis effort that used a drone to determine various water quality and water clarity parameters,” says Halfman.

Flying the drone about 100 meters high, Bradt took photos that were assembled into a composite image after each flight. They were a challenge to read, she says, as factors such as the level of the sun, waves, suspended sediments, clouds and shoreline trees made it hard to distinguish the algae blooms. Following two summers of work, however, it was possible to come to some conclusions about the BGA.

“[Bradt’s] maps indicate that the really concentrated blooms are most prevalent along the shoreline, and typically dissipate to significantly lower concentrations by 10 to 20 feet away from shore,” says Halfman. “It means that the nutrients must come from the shoreline area, and suggests that decaying aquatic weeds, zebra/quagga mussels and other organisms living in the shoreline area and washed up along the beach provide the nutrients (fertilizer) for the BGA blooms.”

Bradt, who intends to work in a geoscience field such as geology or hydrogeology, hopes the research will help determine which of the Finger Lakes are experiencing invasion by the BGA and macrophytes and what controls can be put in place. “This could be used by others to predict when nutrients [in the water] will fertilize the blooms and become noticeable in the lakes,” she says.