The Water Summit of May 11th- A Great Learning Experience About Cyanobacteria

About 150 people attended the Third Water Summit sponsored by the Wentworth Watershed Association. An impressive set of speakers let us know the good, the bad and ugly about Cyanobacteria. These are not actually algae, they are very different and evolved billions of years ago. At that time, there was literally no oxygen in the Earth’s atmosphere or oceans so they lived without it. For this reason, they can presently survive where other organisms can’t. Our lake bottom, in the summer, is very oxygen poor but these guys are fine and get the phosphorous that they need and then periodically rise to the surface and cause problems. They can produce toxins that are harmful to humans, pets and other organisms. We do have to worry about them…..

The cyanobacteria have an interesting life cycle in that they tend to not be an issue until mid to late summer in our area. Then, they may come to the surface and cause problems. Often, in the middle of the lake, they are hardly visible but the wind can move them into bays and they form a green scum. In these concentrations, people should be aware of risks associated with them and avoid jumping in, letting pets jump in, or drink the water. Last Summer this was a very real problem in Winter Harbor.

The bacteria require phosphorous to grow so any addition of phosphorous to our lakes is bad. This is why you never should use fertilizer on your lawns that has the middle number other than a “0”, which means no phosphorous. (The phosphorous makes plants want to bloom and you don’t need your grass to bloom…..) We also need to try to reduce the amount of storm run-off going into our lakes as the soils have phosphorous in them. This is why people are building rain gardens or areas where storm water can collect and seep into the groundwater instead of going directly into the lake. Information is available on-line and through the Wentworth Watershed Association office. The Town is also working to reduce run-off into our lakes building similar collection areas.

Basically, the more storm water run-off that enters the lake, the more phosphorous from any source such as lawns or pet waste increases the risk of larger blooms of cyanobacteria. We also need to monitor the growth and development of the bacteria and a workshop will be given at Brewster Academy on June 26th for those interested in monitoring this problem. No scientific background is required, just a desire to help. The Wentworth Watershed Association also now is in the possession of a device that can detect levels of the cyanobacteria in lake water so you can find if there are issues or not an issue on a given day.

One further comment is that many of the questions and answers from this Summit will be put on the website when available and I hope it is soon. If you have questions or want to find out how you can help, contact the Watershed office. 534-0222

Below, Don Kretchmer is asking questions from the audience of the three main speakers.

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