This spring Ballston Lake has had a larger than normal bloom of the slimy mat like algae called spirogyra. The conditions for any algae bloom are:
1.Warm water: Ballston water temp on May 25 was 74 degrees
2.Lack of mixing due to wind or wave action
3.Clear water: Ballston clarity reading on May 25 was 2.5 meters
4. High phosphorous levels
5. Deep light penetration - Spirogyra develops at the bottom of the lake where phosphorous is available from the sediment. In its photosynthesis it gives off oxygen and rises to the surface and grows into large mats. Its presence is thicker in water 10 feet deep or shallower. On the surface the algae is exposed to the sun and deteriorates and dies then sinks back to the bottom. It then becomes a source of phosphorous for future algae growth.
Spirogyra can be treated with an algaecide to kill it. The following is information about algecide use:
1. Copper base products are toxic to many desirable lake species of life so they must be used sparingly.
2. Algaecides can be sprayed to the algal mats but for effect the mats must be broken up so the chemical can contact the algal cells.
3. The lake is closed for recreation for 24 hours after an algecide application.
4. One treatment is not effective for algal removal so reapplication must be considered especially with a high density algae.
5. Algaecides have a short effective time frame and have the best effect in water with a pH above 8.0. Ballston’s pH is 7.5.
6. Algaecides must be applied by a company licensed to do so. Cost for application varies with the area of algae to be treated. Whole lake cost could be about $30,000 per application.
Of all the algae we have, spirogyra is a nuisance algae and will soon be gone due to water temperature. The blue green algae microcystis that develops in the lake when water temps are about 76 degrees in July and August is of a greater concern. This algae can produce a toxin microsystin. Prevention is the best way to control any algae bloom in Ballston Lake. BLIA is working to use its limited funds in the best way to :
1. Reduce phosphorous levels in the lake
2. Encourage watershed residents to pump out their septic tanks every 3 years.
3. Encourage lake side residents to remove plant debris from their shorelines.
4. Reduce erosion of shorelines and reduce sedimentation of streams that feed the lake