Living with algae at Clear Lake

Algae has been part of Clear Lake for the more than 2 million years the lake has existed. A common name for the algae is cyanobacteria. The amount of algae in the lake varies from year to year. Some years the water is relatively clear and you can see down a far as 6 feet. Other years the algae is so thick you can only see down about a foot. There are 130 different species of algae in the lake.

Cynobacteria is often called blue-green algae although it is not related to any algae species. For argument's sake, we will refer to it as algae. It is actually a living organism and is one of the oldest living fossils in the world, going back billions of years. It lives in the water and reproduces by photosynthesis, which means that sunlight causes it to bloom and make its own food. Even though many people hate it, blue-green algae does serve a purpose. The plant produces oxygen, which all living things require. In fact, various forms of algae produce 70 percent of the oxygen on our planet and without it we couldn't live.

Algae are actually tiny water plants that cycle normally between the bottom and the surface, floating up and sinking down. During the day, algae generates oxygen within the lake and at night it consumes oxygen. Without question algae are one of the most important plants in existence. Algae not only produces oxygen, but it provides food for many of the creatures in the lake. Baby fish feed on plankton that is part of algae.

Cyanobacteria can be a problem. From more than 130 species of algae and cyanobacteria identified in Clear Lake, five species of cyanobacteria can create problems under certain conditions. These problem cyanobacteria typically bloom three times a year — in the spring, summer and late summer. Each bloom is dominated by a different species of cyanobacteria that thrives in the prevailing conditions at that time of year. The intensity of the blooms vary from year to year and are unpredictable. The problem occurs when cyanobacteria blooms are trapped at the surface and die. When this occurs, unsightly slicks and odors can be produced. Some cyanobacteria may produce cyanotoxins that can pose a range of health risks to people and animals. This is what has happened in past years in the Clearlake Oaks arm and other southern arms of Clear Lake. Every portion of the lake will experience algae blooms at some point.

Algae is nothing new to longtime Lake County residents. Forty years ago the algae was so thick at times you could hardly run a boat through it. Boats going across the lake would produce bright green wakes. Swimmers would leave the lake and have a green color on their bodies. Actually, Clear Lake is getting clearer. According to scientists, the lake is now clearer that it has been in the last 50 years. There are also side effects from a clearer lake and that is aquatic weed growth. Years ago when the green and blue-green algae was thick the sunlight couldn't reach the bottom of the lake to generate weed growth, there were very few weed mats.

Getting rid of all the algae can be a difficult task. The county doesn't have the resources to eliminate the algae and even if the county did, it would take years. In the past the county has installed inflatable booms at the entrances of some of the harbors such as Redbud Park in Clearlake and at the boat ramp in Clearlake Oaks. The county also has used boats equipped with pressure hoses to break up the algae mats. All these methods have met with limited success. The problem with the algae, in addition to the thick mats, is the stench it creates when it rots. In some areas the stench can be so great that lakeside residents can't sit out on their decks in the evenings. Thick algae mats can also clog up intakes on outboard and inboard motors, which can result in major damage.

Make no mistake, blue-green algae can cause serious problems for the users of Clear Lake. Depending on its stage it can cause a problem if you drink it or it comes in contact with your skin. It can also kill animal, especially dogs, that swim in the lake. Typically a dog will lick its fur after coming out of the water. If the dog has been in the green-blue algae it can ingest some of the algae.

The good news is most of the cyanobacteria will be gone by October and the water will once again be clear. Clear Lake didn't get its name from being clear, by the way. It was named Clear Lake because of the clear air around the lake. Clear Lake has been constantly changing for thousands of years and will continue to do so.

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