The state Department of Environmental Conservation (DEC) in November discovered Lake George’s first harmful algal bloom (HAB) in Harris Bay.
The Jefferson Project at Lake George, a collaboration between RPI, IBM Research, and the nonprofit FUND for Lake George, immediately deployed resources to examine the situation.
More than 20 researchers collected water samples from across the lake for sophisticated chemical, biological, and computer modeling analyses. They also deployed advanced sensors around the lake (including Harris Bay), officials said.
The algal bloom was first observed in Harris Bay on Nov. 7 and dissipated that same day, according to the FUND for Lake George. Additional blooms appeared on Monday, Nov. 9, in Harris Bay, Sandy Bay, Warner Bay, and near shore waters off of Lake George Village, all of which dissipated within 24 hours.
It was verified that the threshold of cyanobacteria concentrations in excess of 25 micrograms per liter were present. IBM and RPI supercomputers and researchers began computationally modeling recent weather and water circulation at all levels of the lake.
All of this effort, officials said, is aimed at answering three critical questions.
“The first question is: Was this a natural event or is this an early warning sign of human activities impacting the lake, due to factors like increasing nutrients or global climate change? Our rapid response to the recent HAB event in Lake George and similar occurrences in lakes across New York state puts us in a unique position to answer those questions and provide insights to decision makers,” said Dr. Rick Relyea, director of The Jefferson Project and a professor of biological sciences at RPI.
The initial results confirm the widespread existence of dolichospermum fuscum—a cyanobacteria commonly found in Lake George and other lakes in abundance below the lake’s surface in autumn—in high concentrations in the recent surface blooms.
The algae are known to have little pouches that make it possible for them to float in the deep waters of the open lake, but its buoyancy is so weak that it can only rise to the surface under extremely calm conditions, according to researchers.
“Since dolichospermum requires at least two days to reproduce, the high density of cyanobacteria observed in Lake George indicates that the algae were likely growing for many days or weeks in the cool water before surfacing.
This surfacing during the HAB was likely enabled by calm water conditions and then driven into these bays and near shore waters off of Lake George Village by wind or water currents according to preliminary computer models” said Dr. Harry Kolar, Jefferson Project associate director and IBM fellow. “Further work continues on the sources of the algae and nutrients required to trigger and sustain the bloom, including the lake bed and watershed runoff.”
“The second important question is: Was this a toxic bloom?” Relyea said. “Some dolichospermum species are capable of producing toxins that irritate the skin and can harm the liver and nervous system and hence we need to know whether the Lake George HAB was toxic (as seen in other lakes).”
Analysis by the Jefferson Project water sample has confirmed the initial results of DEC. Toxins were not detected.
“The third critical question then remains: While not observed in this bloom, could toxic blooms occur in the future on Lake George?” Relyea said.
Jefferson Project research is now fully investigating and delving deeply into the drivers of toxicity in these algae, he said. The work is leveraging RPI’s Center for Biotechnology & Interdisciplinary Studies (CBIS), coupled with IBM’s and RPI’s most advanced sensor networks and supercomputing, which officials said is the most powerful ever deployed on any freshwater ecosystem.
