Terry Knight — R-B Outdoor Writer
LAKE COUNTY ? Dr. Harry Lyons, professor of ecology and biology at the Yuba College Clear Lake Campus and a marine biologist, dazzled and entertained a standing room only crowd at the Clear Lake State Park on Saturday. Lyons gave a two hour lecture on the health of Clear Lake.
According to Lyons, Clear Lake is at least two million years old. “It”s the oldest lake in North America if not the Western Hemisphere. In fact, I think it is much older than two million years,” Lyons said. He also said the algae has been part of the lake for its entire existence.
Lyons said the nuisance blue-green algae (cyanobacteria) that is now choking the south end of the lake is more than two billion years old. He said it is one of the earth”s oldest living fossils. They are unique in that they are completely independent and generate their own food through photosynthesis. They also have no enemies.
According to Lyons, despite what many people think the algae is beneficial to the health of the lake. As the algae dies and sinks to the bottom it decomposes and provides food for the smaller aquatic creatures such as snails, crustaceans and insects which in turn are eaten by the fish. In other words the algae is an important part of the food chain. However too much blue-green algae can also cause problems by using up the oxygen in the water.
Lyons said that Clear Lake is actually getting clearer and this year”s algae explosion could just be a spike. He said that he has been checking the lake”s water clarity for many years and is definitely seeing an improvement.
He said that because of the thick blue-green algae some people have called Clear Lake a “sick” lake. “I don”t call the lake a sick lake but instead a fat lake that needs to go on a diet. What I mean by a fat lake is that there are too many nutrients washing into the lake and it is causing an excess of algae blooms,” said Lyons. He said that 85 percent of the shoreline has been changed by humans and protecting the shoreline is vital. That includes controlling grading on the nearby land as well restoring the Rodman Slough area which will go a long way towards cleaning up the lake.
Lyons said the algae is moved around the lake by the prevailing westerly winds. He said that wind action can penetrate down to a depth of 18 feet and with average depth of the lake being only 18 feet, the winds stir up the algae and cause it to drift.
A member of the audience asked if it would be profitable to harvest the algae. Lyons said no. The reason being that it would cost more to harvest and process the algae than it could be sold for.
Several people wanted to know if dredging the lake would cure the algae problem. Lyons said that it would but the lake would have to be dredged to an average depth of more than 60 feet which would be impractical. He said that dredging the lake would also stir up the mercury that”s on the bottom as well as the layers of pesticides that were put in the lake many years ago to control the gnats.
A question was asked about the impact of the quagga mussel on the lake”s ecosystem. Lyons replied that in his opinion it would forever change the lake. The mussels would feed on the algae which in turn would destroy the food chain and the fishery would suffer. He said that Clear Lake would be clear but lifeless.
A final question was asked that since the lake has been a green color for much of its existence, when and how did Clear Lake get its name. Lyons said that he had no idea and thought the lake was misnamed.
Lyons, who is an accomplished musician and song writer, finished his lecture with a song about Clear Lake and its algae. As one member of the audience put it, “Dr. Lyons is a Lake County treasure.”
