Experts outline water quality concerns
GENEVA--The Seneca Lake Pure Waters Association (SLPWA) gathered experts for a packed summit Saturday, March 24 to talk about the issues facing Seneca Lake and the other Finger Lakes. This included harmful algae blooms and stormwater runoff.
SLPWA is a volunteer-run organization founded in 1991, and it is managed by a board of volunteer directors. The association is funded by memberships and grants, and they collaborate with the Finger Lakes Water Hub, the Community Science Institute, the Finger Lakes Institute at Hobart and William Smith Colleges, and the Seneca Watershed Municipal Organization. Their goal is to improve and protect the water quality of Seneca Lake.
Seneca Lake is the deepest freshwater lake east of Mississippi outside the Great Lakes. Its average depth is 290 feet, but its deepest point is over 600 feet. It is 38 miles long and averages two miles wide, holding 4.2 trillion gallons of water. The temperature at the bottom of the lake remains 39 degrees year-round. Its immense size gives it the longest retention time of the Finger Lakes at 18 years, so improvements may take a while to make themselves apparent. It's also the Finger Lake with the highest salt content.
The two main programs SLPWA is working on are Harmful Algae Bloom (HAB) monitoring and stream monitoring. Their findings suggest these go hand-in-hand.
For the former, they have almost 100 volunteers and a HAB hotline, which people can report suspicious blooms around them. 2017 was the first year with HABs verified in all 11 Finger Lakes.
For the latter, there are more than 50 volunteers collecting samples from five streams, five times per year. The samples are then observed by the Community Science Institute, a non-profit organization with a certified water quality testing lab, and tested for phosphorus, nitrogen, E. coli, solids, temperature, pH, and dissolved oxygen.
The takeaway is there are larger impacts in high-flow areas. Elevated phosphorus levels, more bacteria, and erosion is causing problems. Data found much higher concentrations of everything tested for in stream water, especially after rain. Stormwater, when unable to soak in, runs along the ground and picks up chemicals and nutrients from oil, fertilizer, litter, etc.
In addition to more nutrients to feed the algae blooms, stormwater runoff brings its own dangers. Stephen Penningroth, the executive director at Community Science Institute, said "When you look at look at stormwater E.coli, you see a really quite spectacular increase in the bacteria count."
Not all algae blooms are harmful, HABs are blooms which release toxins dangerous to humans and animals. It is not possible to tell just by looking at a bloom if it is harmful, so it is important to never swim in potentially dangerous water. HABs can look like spilled paint, pea soup, foam, wool, streaks, or green globs.
The Community Science Institute's monitoring found in the summer of 2017, there were no recorded HABs, but from September 14 to October 3, there were 60 reported blooms. Of those 60, 50 were confirmed. Of those 50, 22 were confirmed high toxin blooms (>20 mcg/L microcystin, a liver toxin) and 21 were confirmed to have measurable amounts of anatoxin, a neurotoxin.
Dr. John Halfman, a research scientist with the Finger Lakes Institute and a professor at Hobart and William Smith Colleges, explained the connection between HABs and the streams entering the lake. He began by explaining the nutrient cycle in the lakes. Dissolved nutrients are eaten by plankton, which are eaten by fish, mussels, and other organisms. These organisms then die and are broken down by bacteria, which releases dissolved nutrients into the water.
Water clarity is determined by the dissolved nutrients, so darker water has more organic material.
The blue-green algae thrives when it has more nutrients, which is usually at the shoreline. Blue-green algae thrives just after the temperature cools down from its hottest. It prefers calm water and usually grows after a rain event. In Owasco Lake, the two largest blooms grew in the calm water after storm and temperature dip events.
Halfman believes major HABs are caused by an influx of nutrients at the shore brought by the wind, rainwater, and decomposition of seaweed and mussels at the shoreline. He thinks waves toward the shore kick up mud and algae from the bottom of the lake which divide rapidly in ideal conditions.
To help mitigate blooms growing in the lake, he said to remove lakeside organic material and reduce nutrient-loading to the lake. Halfman jokes, "One thing I implore you never to do is to use a herbicide. We drink the water. You kill them off, you kill us off. I don't wanna get killed off."
Lewis McCaffrey, a research scientist at the NYS DEC Finger Lakes Water Hub, said "Eutrophication, that is when a lake is becoming highly concentrated with nutrients, that can be a natural process. You'd actually expect a lake, once its been formed, to go through a whole series of transformations from a lake eventually through to a meadow. I've done some calculation with sedimentation rates and maximum depths and don't worry, Seneca Lake has got around 90,000 years before it becomes a meadow. It is a natural process, but unfortunately, humankind has increased the rate of eutrophication."
For those interested in volunteering to help improve the longevity of Seneca Lake, visit senecalake.org for more information. To report suspicious blooms, email email@example.com or call 1-800-220-1609.