By Dana Little, June 21, 2014.
Jumping into shallow water in late summer and early fall may land you in a mass of large, green, slimy blobs. The blobs, called metaphyton, are actually collections of algae. At least two processes can produce metaphyton. 1. Algae floats freely in the water throughout the year, some in the form of long, green, hair-like strands. During the summer, winds blow these floating strands around until they collect into large clumps. The clumps tend to become trapped by plants growing in shallow areas. With time, more strands collect until they form large masses several feet across. 2. A second process of production starts with large mats of algae growing on the pond floor in shallow areas. As photosynthesis occurs, the resulting oxygen becomes trapped in the algae mat, lifting it upwards until a large green blob filled with bubbles appears on the surface.
Another name for metaphyton is elephant snot. Experts believe that despite the disturbing look and the slimy texture of metaphyton, they are a normal part of a healthy pond. Metaphyton are an excellent source of nutrition for aquatic insects, crustaceans, frogs and small fish. In addition, they provide shelter from predators for small pond creatures. Phosphorous and nitrogen run-off from lawns and developed areas increase the production of metaphyton. Installing a buffer zone of natural vegetation next to the water, and avoiding the use of chemical fertilizers help keep elephant snot to a minimum.