Hot summer days and nights at Clear Lake means algae and Clear Lake has its share of it this year. Actually, algae has been a vital part of Clear Lake during its entire 2-million-year existence. Bottom core samples taken by scientists show that Clear Lake has always been a rich and fertile lake, and algae has been a part of it. Clear Lake didn’t get its name from the water clarity but from the clear air around the lake.
According to Carolyn Ruttan of the Lake County Water Resources Department, what we are seeing on Clear Lake is not true algae but cyanobacteria. For argument’s sake, we will refer to it as algae. 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 they consume oxygen. Algae are among the oldest living organisms on our planet, going back at least 2 billion years. Without question algae are the most important plants on earth. They generate 70 percent of the oxygen in the atmosphere and without algae there would be no life on the planet.
Algae is nothing new to longtime Lake County residents. Thirty 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 University of California scientist Greg Giusti, the lake is now clearer that it has been in the last 50 years. Giusti said there are also side effects from the clearer lake and that is aquatic weed growth. Years ago when the green and blue-green algae was heavy and sunlight couldn’t reach the bottom of the lake to generate weed growth, there were very few weed mats This year because of the clearer water it is expected there will be heavy weed growth during the summer months. Giusti said 50 years ago the shoreline of the lake was covered with tules and not aquatic weeds.
A number of people are asking if it’s safe to swim in the lake. According to county officials, the lake is safe to swim in but care should be taken to avoid the areas with thick blue-green algae (cyanobacteria). Algae blooms can change from day to day. A good example is the Fifth Street Ramp in Lakeport. On Saturday, the algae was thick and ugly looking but by Monday morning the water was relatively clear with no algae. Upper Blue Lake is another good example. Normally the lake is very clear but this year the lake is actually greener than Clear Lake. Ruttan said the green color is caused by cyanobacteria, which has never occurred before in recent memory.
Getting rid of all the algae is an impossible 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.
One area that could be improved is educating the public about algae and the aquatic weeds. The public needs to know what types of algae there are in the lake and what the county is doing about it. For example, even if all the nutrients algae need to survive were stopped from entering the lake, there are still enough presently in the lake to keep the algae alive for many years. In other words, it would take at least 50 years to solve the algae problem. The public needs to know that. The good news is the algae will be pretty much gone by late September and the lake will once again be clear.
