Have you ever wondered what that slimy green/ brown stuff covering rocks or floating in the water was? What you were looking at was algae. Algae, like plants, use the sun to make energy (photosynthetic organisms), and are food for a variety of animals including fish, bugs, and birds. Algae differ from plants by not having true roots and leaves.

Also like plants, algae need light and a food source to grow. Algae loves phosphorus and nitrogen that enter the water. If these nutrients enter the water excessively, algae can bloom and become a nuisance and potential health hazard. When algae blooms it can become toxic, clog intake pipes and discourage swimming and other recreational activities.

Algal blooms have been found in bodies of water throughout the Adirondacks, some of the most noted in Lake Champlain where blue/green algae or cyanobacteria can be found. These algae can form toxic blooms that can harm humans, pets and wildlife. Not all algae produces toxins, in fact most algae does not.

Lake George has been also been experiencing algal blooms. Algae there is found in the littoral zone, or near shore and is mostly green algae with very little blue/green. Generally algal blooms within Lake George are caused by lawn fertilizers washing into the lake, faulty septic systems, and storm water.

Excessive amounts of algae can also cause a dead-zone within a lake, an area of the water that has no oxygen and thus no fish. If you see an algal bloom in Lake Champlain contact the Lake Champlain Committee at (802) 658-1414 and report time of day, location and a description. Algal bloom in Lake George should be reported to the Lake George Waterkeeper.

While excessive amounts of algae are bad, it is a natural part of the aquatic environment. Algae can also be used by a trained scientist to determine if a body of water is healthy.

There are a variety of types of algae that can be seen in almost any body of water, including your fish tank. One of the more interesting types, looks like a ribbon twisting in a glass bottle. This form is often found in Lake George.

Photos: Above, spirogyra; Middle, cladophora; Below, mixed diatoms. Courtesy of Corrina Parnapy.