California is dyeing a lake pink. Here’s why:

Above: Bioluminescent waves at a beach in Southern California.

( KTLA ) – A lake in Northern California is getting a dye job, but it’s not to improve its aesthetic. No, this makeover will serve an important function.

Researchers from the California Department of Water Resources are dyeing McLeod Lake in downtown Stockton, turning it from its greenish-blue hue to a muted pink.

Scientists from the California Department of Water Resources added rhodamine dye to McLeod Lake in Stockton to study how water moves throughout the lake in hopes of learning more about harmful algal blooms on Aug. 27, 2024. (CA DWR)

It’s part of a study that researchers hope will shed some light on a question they’ve been unable to answer: Why do harmful algal blooms happen some years but not others?

In 2022, McLeod Lake was the site of a harmful algal bloom that turned the waters into a vibrant shade of green. But in 2024, the lake has been fine much to the surprise of researchers.

So, what gives?

Lake McCleod was the site of a harmful algal bloom in 2022, but no such bloom has taken place in 2024, much to the surprise of researchers. (CA DWR)
Lake McCleod was the site of a harmful algal bloom in 2022, but no such bloom has taken place in 2024, much to the surprise of researchers. (CA DWR)