What causes that green floating stuff in my lake that looks like fluffy clouds or cotton candy?
It’s probably filamentous algae, sometimes called “moss” or “pond scum.” This is a common and troublesome aquatic plant that forms dense, hair-like mats in shallow water where sunlight reaches the bottom of the pond or lake. As the algae grows, it produces oxygen that gets trapped in the entangled strands of algae. This entrapped oxygen makes the algae buoyant and causes it to rise to the surface of the pond or lake. Some of the more common forms of filamentous algae can be identified by their texture, although microscopic examination is usually required for exact recognition. Cladophora feels “cottony,” while spirogyra is bright green and very slimy to the touch, and pithophora (or “horse hair”) has a very coarse texture like horse hair or steel wool. The best method for homeowners to remove filamentous algae is to rake out the floating clumps and limit the nutrients that reach the water from your property. You can compost these piles or use them in your garden as mulch. Remember, che
