Aquatic Plants and Algae Found at Cupsaw Lake

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This type of algae is enemy #1 for recreational lakes.  It is the type of algae that can lead to a Harmful Algal Bloom (HAB).

Diatoms are a good algae.  They are a planktonic algae, meaning they float through the lake water and are not rooted.  They are the base of the food chain.  Their brown tint can be seen in the lake when they are dominant from late fall through late spring.

Cattail is a beneficial plant for the lake, but too much can be a problem.  It is beneficial because it soaks up nutrients and can even filter water from streams.  It spreads quickly and can block lake access, so it is monitored and pulled when needed.

Curly-Leaf Pondweed emerges each winter at Cupsaw Lake.  It continues to grow well into the summer if left untreated.  It will die naturally in late July, but this is a bad time for it to decompose in the lake, so it is treated in May.

There are native naiads that are good for the lake and there are invasive naiads.  Both are present in Cupsaw and are often seen at the end of the swim season.  They will detach from their roots and float around Labor Day.  We have not experienced them at nuisance levels.

Lyngbya is cyanobacterium (blue-green algae). Unlike the cyanobacteria that makes the lake green, lyngbya is a filamentous form of cyanobacteria. Lyngya has a sheath around it that makes it tough to treat with chemicals and our sonic devices will have little impact. 

Lyngbya will grow along the bottom, but eventually trapped gases will cause it to rise to the surface and die. Below the surface, streamers will continue to live and photosynthesize. The mats at the surface can reach nuisance levels. 

Unlike planktonic cyanobacteria, lyngbya is not a lake-wide threat, but can completely cover coves. It will also give off a bad, earthy smell as it naturally dies on the surface. Swimmers should avoid large masses of lyngbya as some people may be sensitive to direct contact.

Lakefront homeowners can harvest this weed and transport it away to improve their lakefront environment. Due to its filamentous qualities, chemical treatments are not very effective.