Biochemist Talks About Harmful Algal Blooms

Dr. Gregory Boyer presented a lecture on harmful algal blooms, how they are created and what can be done to reduce their effects on the local level. P-J photo by Eric Zavinski

There is no silver bullet to rid Chautauqua Lake of its harmful algal blooms.

According to Dr. Gregory Boyer, the speaker for the 14th annual Maurray L. Bob lecture at the Prendergast Library, the prevalence of cyanobacteria, otherwise known as blue-green algae, in the lake is a problem that will best be solved with a combination of various best management practices.

Boyer currently works as the director of New York’s Great Lakes Research Consortium and chemistry professor at the State University of New York College of Environmental Science and Forestry in Syracuse. He has previously worked as the director of National Oceanic and Atmospheric Administration’s Lower Great Lakes project, for which he helped develop strategies to monitor blue-green algae. He has a Ph.D. in biochemistry from the University of Wisconsin. His research on algal blooms and toxins lent itself to a discussion regarding the definitions of such elements, why they exist and what can be done to prevent societal, economic and environmental harm.

“You are not alone in having harmful algal blooms,” Boyer said.

Definitions

Boyer opened by describing the elements that characterize a harmful algal bloom. He discussed how a bloom is a growth of microscopic organisms in the water column that reach elevated concentrations.

Blue-green algae specifically is a specialized photosynthetic lifeform that has evolved over the past three and a half billion years.

With such a long evolutionary timeline, Boyer said the bacteria has learned to cultivate specialized cells to use nitrogen and other nutrients to grow. These organisms can also control their buoyancy in response to light, meaning they can disappear below the surface when sunlight gets too harsh in the mid-day periods and rise back up to absorb more light. They usually concentrate near the shoreline and docks due to wind that blows the algae.

What makes the algae harmful are the toxins it can produce. Boyer mentioned some toxins are deadly, including the red-tide that can lead to fish kills and the deaths of other marine wildlife. Harmful algal blooms can deplete oxygen, resulting in fish kills as well since the oxygen is scarce in the deeper parts of a lake, forcing fish to swim near the surface and sometimes die due to heat stress.

Why They Grow

Six factors contribute to the growth of harmful algal blooms. Seed population, grazing from other species such as zebra mussels, warm temperatures, calm winds and sunlight are five factors we can’t control, leaving the sixth factor, nutrients that serve as the food for these bacteria, as the remaining element Boyer said humans can affect.

“Nutrients are the only thing we can effectively impact,” Boyer said. “It’s not the only thing that’s important, but it’s what we can control.”

Boyer also noted that global climate change predicts longer growing seasons for bacteria, with warmer falls and calmer winds. Phosphorus is the primary nutrient that contributes to algae growth, and for Chautauqua Lake, it comes from a variety of different sources.

Local Impact

“You’ve got way too much phosphorus in this lake,” Boyer said during his take on the nutrient issue in Chautauqua County.

While the Department of Environmental Conservation issues a guideline for 20 micrograms per liter of phosphorus in a body of water, Chautauqua Lake far exceeds that with 50 micrograms per liter in the north basin and 100 micrograms per liter in the south basin.

Accordingly, the level of algal blooms in the water is 20 micrograms per liter in the north basin and 50 micrograms per liter in the south basin, both exceeding the 10 micrograms per liter guideline set by the DEC.

Boyer mentioned Chautauqua Lake is a historically eutrophic lake with a high variability of shoreline algae, explaining the drastic differences seen on shorelines throughout the lake.

“It seems like the toxicity of the lake is going down,” said Boyer, but he also pointed out that doesn’t mean algal blooms themselves have decreased over the years.

A lake rich in phosphorus still leads to additional blooms and the subsequent lower water quality, less recreational enjoyment, worse economic viability and potentially adverse health effects.

Best Management Practices

“Best management practices are local,” Boyer commented, meaning that not all solutions work in every area.

He said that a combination of best management practices, including ways to manage stormwater runoff, are ideal. Boyer also said there are usually trade-offs; for example, if pine trees that absorb runoff are planted as a buffer along a shore, the views of lakefront property owners are jeapordized.

“In most cases, everybody doesn’t win,” Boyer said.

For the north basin, he reported approximately 12 percent of phosphorus stemming from agricultural use of surrounding land, 20 percent from point sources such as septic systems, 25 percent from internal loading and 37 percent from groundwater.

The south basin receives its phosphorous from these sources in drastically different amounts, with approximately 55 percent originating from internal loading, 15 percent drifting from the north basin, 21 percent coming from groundwater, and other sources providing very little phosphorus in comparison.

Boyer said phosphorus from internal loading is difficult and expensive to control, requiring dredging for a large body of water. He then added that the county has a detailed lake watershed management implementation plan that targets 18 high-priority area for implementation of best management practices and 36 high-priority capital projects that could help reduce nutrient runoff.

Recommendations included planting trees, plants or grass in buffer zones from a shoreline to 50 feet back. Boyer also suggested avoiding installing impervious surfaces like parking lots within that distance of the lake. He also said to rethink the design of drainage ditches by adding artificial wetlands and bioswales to soak up more water. Stream bank stabilization and other engineering projects could also be implemented to help direct runoff away from the lake.

“There is not going to be one thing that turns the lake around,” Boyer said.

He hopes residents won’t be paralyzed by the number of possibilities and added that no one really knows how effective a best management practice can be before it is implemented.

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