Clear Lake’s Spectacular Emerald Surge: A Green Algal Bloom Captivates California!

A significant algal bloom has occurred in Clear Lake, California, one of the state’s oldest and most popular tourist destinations, causing the water to become cloudy and green. NASA satellite images have captured this dramatic change, revealing a notable difference in water quality compared to the same time last year. The bloom may be due to blue-green algae, or cyanobacteria, which produce microcystin, a toxin that can cause skin irritation and liver and kidney damage.

Algal blooms in Clear Lake have historically been common, but their frequency has increased with human activity in the last century. Factors contributing to water quality issues in the lake include runoff from nearby farms, vineyards, faulty septic systems, gravel mines, and an abandoned open-pit mercury mine. Furthermore, some nutrients exist in the lake bed’s sediment and are mixed into the water by waves and nonnative carp.

Clear Lake, covering 43,000 acres and possibly the oldest lake in North America, is the central attraction for several communities in the Lake County area, including Lakeport, Clearlake, Kelseyville, and Glenhaven. The main attractions of boating, fishing, and swimming may be affected by the algal bloom for several weeks, officials have warned. The bloom was at its peak on May 15, 2024, as captured by a NASA satellite image, with toxicity monitoring data yet to show its presence, and the next sampling scheduled for June 4.