Stockton's McLeod Lake is looking pretty pink this week.
The splash of color is part of a study being conducted by the California Department of Water Resources, which is pouring a pink dye into the water to find out why the lake has become a hotbed of harmful algae.
Dangerous algae blooms that can be toxic to humans, pets and aquatic life appeared in McLeod Lake in 2020 and 2022 — but, interestingly, not this year. So scientists are using the dye to record water flow, which they hope will answer the question of why algae blooms some years and not others.
Teams began pouring rhodamine dye into the water on Monday and will complete the study on Friday, according to a news release.
The dye is temporary and harmless to humans, but it is clearly visible. KCRA 3's video showed the blue-green water turning a deep purplish pink as crews used long poles to evenly distribute the dye at different depths.
Blue-green algae, known as cyanobacteria, are a natural part of the ecosystem, but they can grow rapidly under certain conditions, including warm temperatures and calm waters. When algae “bloom” so quickly, they can produce toxins that cause loss of appetite, vomiting, and even jaundice and hepatitis in swimmers.
When blooms are large enough, they can cause the water to turn fluorescent green and smell putrid. After a particularly large bloom at McLeod Lake in 2006, Stockton installed a bubble system in the Stockton Deepwater Channel to oxygenate the water and break down the algae, the Record reported.
The dyeing work is the first of two studies that scientists are conducting at the lake. The next is expected to be scheduled for early next year.
