Recreational Lakes & Reservoirs
Whichever the primary use of a waterbody (raw water drinking source, recreational, small lakes & ponds, stormwater, etc), the key component for effective cyanobacteria (blue-green algae) control is to actively circulate just the upper water of the lake known as the epilimnion.
Active Lake Circulation Solutions
Medora's active lake circulation solutions can treat large areas with our leading solar-powered SolarBee® Lake Circulators (up to 35 acres per circulator) and smaller, nearshore areas with our air-powered AerationPlus© Lake & Pond Circulators (up to 5 acres per circulator).
How does active epilimnetic circulation reduce or eliminate cyanobacteria?
There are four main mechanisms...
1) SolarBee® active circulation helps the "little creatures" in the epilimnion, the algae and bacteria. It eliminates the problem of bacteria being limited by organic carbon, so that all three beneficial organisms, good green algae, diatoms, and bacteria can compete to use up the dissolved nitrogen (N) and phosphorus (P) in the epilimnion all season. Since good green algae and diatoms start early in the spring, circulation causes the epilimnion to stay "short" of N and P all summer so that cyanobacteria can never get enough N and P to gain traction. At the same time, the good green algae and diatoms are constantly kept cropped down by zooplankton, so there is never a "bloom" of these algae, and the lake stays clear all year.
2) SolarBee® active circulation takes away the buoyancy-adjusting advantage of cyanobacteria. It pulls in good green algae and diatoms that were about to fall through the thermocline and elevates them back into the sunlight at the top of the lake, and it also pops buoyant cyanobacteria up to the surface of the lake where most species are destroyed by sunlight.
3) SolarBee® active circulation aids the zooplankton. By helping the green algae and diatoms, the zooplankton numbers stay high, including the larger daphnia. Then, when other food is gone, the large daphnia will crop down cyanobacteria to some degree.
4) SolarBee® active circulation helps spread cyanophages, viruses of cyanobacteria, which kill 30% of cyanobacteria naturally even without circulation.
What about wind mixing?
Wind mixing is not always reliable or effective. With wind mixing, all streamlines are parallel and very shallow (perhaps a foot or two deep). The only effect is to pile water higher on the leeward side of the lake which then creates a "backflow" across the thermocline.
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