Stockton’s McLeod Lake looks pretty in pink this week.
The splash of paint is part of a study being conducted by the California Department of Water Resources, which is dumping pink dye into the water to find out why the lake has become a hot spot for harmful algae.
Dangerous algal blooms, which can be toxic to humans, pets and aquatic life, appeared in McLeod Lake in 2020 and 2022 but — strangely — not this year. So scientists are using the dye to record water flow, which they hope will answer the question of why the algae spread in some years but not others.
Crews began dumping the rhodamine dye into the water on Monday and will complete the study on Friday, according to a press release.
The dye is temporary and harmless to humans. But it definitely shows. KCRA 3 video was shown the blue-green water turned a strong shade of purple-pink as crews used long poles to spread the color evenly at different depths.
The blue-green algae, known as cyanobacteria, are a natural part of the ecosystem but can grow rapidly in certain conditions, including warm temperatures and calm water. When the algae “bloom” so quickly, they can produce toxins that lead to loss of appetite, vomiting and also jaundice and hepatitis for swimmers.
When the blooms are large enough, they can turn the water fluorescent green and make it smell rotten. After a particularly large bloom at McLeod Lake in 2006, Stockton installed a bubble system in the Stockton Deep Water Channel to oxygenate the water and break up the algae, reported the record.
The staining job is the first of two studies that researchers are conducting in the lake. The next one is expected to be planned early next year.