Wildfire Smoke Causes Blue-Green Algae Growth in Lake Tahoe

by Lauren Boisvert

In outdoor news, blue-green algae growing in Lake Tahoe has environmental experts concerned for the lake’s ecosystem. Apparently, the algae are more abundant than they’ve ever been, and that may be in part because of recent wildfires. According to CBS News, there are large growths in the Regan Beach area of South Lake Tahoe, and while there are several types of algae that grow in the lake, some are more harmful than others.

Blue-green algae are toxic to humans, animals, and other kinds of algae that grow in the lake. The good algae keep the lake clean and the water clear. Blue-green algae–known as cyanobacteria and not technically algae at all–on the other hand, kills the good algae.

Lake Tahoe Grows Toxic Blue-Green Algae Aided By Smoke From Nearby Wildfires

Blue-green algae are more likely to produce blooms when conditions are right. The bacteria prefer calm, warm, sunny waters with temperatures above 75 degrees. The heatwave that has been sweeping over the United States has most likely aided in the production of cyanobacteria. Additionally, researchers believe that the smoke from recent wildfires may also be creating the perfect environment for the blue-green algae.

Currently, Lake Tahoe is experiencing a bloom of leptolyngbya, which is a genus of cyanobacteria. According to researchers at UC Davis, the algae thrive when exposed to nitrogen from smoke. Last year, the blue-green algae growth was the largest in recent history, due to smoke from the Caldor Fire.

“Based on what we saw last year, we are expecting this blue-green algae […] to come back,” said Geoff Schladow, professor at UC Davis. Currently, the plan is to shovel the algae off the lake and vacuum it up as it washes to shore. But, Schladow predicts, the nearby Mosquito Fire may make this job more difficult.

Meanwhile, Hood Canal in Seattle Grows Helpful Algae

Earlier this month, a huge algae bloom cropped up in Hood Canal, west of Seattle. The microscopic organisms, called coccolithophores, are expected around this time of year. They create a beautiful turquoise color that can actually be seen from space. But, they’re more than just pretty. They’re also helpful.

Coccolithophores not only feed the zooplankton and shellfish in the canal, but they aid in reducing carbon dioxide in the atmosphere. Michael Carlowicz, of NASA’s Earth Observatory site, wrote in an article that “coccolithophores and other phytoplankton also play an important, but not fully understood, role in the global carbon cycle, taking carbon dioxide out of the atmosphere and eventually sinking it to the bottom of the ocean.”

At first glance, algae blooms might seem detrimental, like the one on Lake Tahoe. But, sometimes, they can be extremely helpful as well, like in Hood Canal. It’s all about perspective, and what type of little organisms you have living in your lake.