Columbus – Residents and visitors may see fountains, pumps and
fleets of motor boats churning the waters of Grand Lake St. Marys
next summer, based on recommendations from Battelle Memorial
Institute for reducing toxic blue-green algae in the lake.
Aeration techniques were among 73 proposals screened by scientists
to fix the environmental problems that essentially closed the
13,000-acre lake to recreation during recent summers.
Battelle researchers worked between June and November to narrow the
initial list of suggestions to 10 viable activities, according to
Harry Stone, Ph.D., who led the project.
A $50,000 grant from the Ohio DNR and the Grand Lake St. Marys
Restoration Commission paid for the work.
Increased water circulation through the use of pumps and fountains
– especially in the lake’s quiet back channels – would keep
blue-green algae from reproducing and blanketing the lake with
blooms, Stone said.
“We even considered using motor boats to circulate the whole lake,”
Early on, researchers realized there would be no “silver bullet” to
solve the lake’s algal problem.
“It will take a combination of technologies,” said T.R. Massey, a
Battelle staff also looked at ways to reduce the amount of
phosphorus and nitrogen flowing into the lake via tributary
streams. Those chemicals, largely the by-products of livestock and
row-cropping operations in the watershed, feed blue-green
Recommendations for addressing those problems long-term were
forwarded to a state task force that is working with area farmers
and civic leaders on the problem, Stone said.
Researchers also screened methods of reducing phosphorus in the
water column through dredging and surface treatment with both
aluminum sulfate and lanthanum clay. The state successfully used
aluminum sulfate to filter cyanobacteria (decaying blue-green
algae) from 4,900 acres at the lake’s center in June.
Battelle staff also recommended a test of lanthanum clay, a
compound developed in Australia, to remove phosphorus from the lake
before it becomes a food source for blue-green algae.
An early-season release of algaecides was a final suggestion.
Stone said algaecides pose a “complicated” solution to Grand Lake’s
problems. Hopefully, these chemicals would work to kill off the
green algae that occur in the late spring and prevent the growth of
blue-green algae later in the season.
Massey stressed the 10 approaches proposed by Battelle are directed
specifically at Grand Lake St. Marys.
While toxic algal blooms are a problem in many of Ohio’s inland
lakes, each of these eco-systems is unique and will require
individualized treatment methods, he added.