I never thought about the cornucopia of algae species until I interviewed Corrina Parnapy, The Fund for Lake George water quality outreach coordinator and resident algae enthusiast.
In the Lake George tributary West Brook, Parnapy has found a rainbow of algae – red, green, yellow-green and blue-green. The species varied by site, and some are sensitive to pollutants. The closer the sampling location to the Lake George Waste Water Treatment plant groundwater seep areas, the less sensitive the species were to pollutants or “trophic issues,” which is the term scientists use for excessive nutrients such as nitrates.
“At the seeps, the primary forms of algae where mixed diatoms. There were no sensitive forms present, and the metrics applied indicated severe trophic issues. These ratings where mirrored in downstream sampling conducted in West Brook, all the way to the mouth,” Parnapy explained in a recent email to me.
Why should you care?
Algae are natural to fresh water flora and important for the ecosystem. But when they rapidly multiply and cause blooms, toxic conditions can follow, specifically when it comes to the blue-green algae, which is technically a bacteria known as cyanobacteria. This has alraedy caused problems in other lakes that provide drinking water. The EPA just awarded grant funding to help with the problem in Lake Eerie believed to be caused by phosphorus in runoff.
“All that would be needed for them to form a toxic bloom is excessive amounts of nutrients, most forms of Cyanobacteria love nitrogen,” Parnapy said.
In the story that ran Sunday about the sewer plant in Lake George, Parnapy mentioned a yellow-green algal called Vacheria she located in West Brook from Route 9 south.
This furry-looking species feasts on high nitrogen levels and is dominating a large bloom in that area among other species including forms of green algae and mixed diatoms, which fish like to eat.
“Within Lake George there are many, many forms of algae, some very beautiful like the desmids. People may have noticed the highly visible near-shore benthic algae blooms, these not only hinder recreation and aesthetics, they smother the substrate. Fish and invertebrates prefer to eat diatoms, so the green algae and cyanobacteria are generally avoided. There (are) many issues that are linked to the excessive algae in the near-shore area,” Parnapy said.
She conducts a routine littoral algae analysis that is provided at no charge to the public. The “littoral zone” is the area close to the shore.
The algae awareness and analysis program aimed at pinpointing what causes excessive growth and helping homeowners find solutions includes littoral zone fly overs to document algae growth two times a year as well as routine near-shore monitoring within the lake and streams. They take samples of events that are out of the ordinary, like the recent spill at The Sagamore resort and the ponds forming in the sand beds at the Lake George WWTP.
“When I collect a sample, I bring it back to my lab and then according to EPA and NYS standards/methods, I identify them to the lowest taxonomic level possible using a microscope. After they have been identified and counted, I apply metrics to them. Some of the metrics I use focus on organic pollution, excessive nutrients, pollution levels, salt levels, and acidity levels. Sampling the algae and applying metrics, along with the physical and chemical monitoring of the water gives us a pretty good idea of what is going on,” Parnapy said.
She's been analyzing algae samples in Lake George and its tributaries since 2008. Every year she has found the same nitrogen-happy Vaucheria.