HABs sampling effort targets Labor Day cyanotoxin levels in L.A.-area lakes

Posted October 30, 2020
North Lake at the Whittier Narrows Recreation Area in Los Angeles County is tainted murky green by a harmful algal bloom in this photo captured shortly after Labor Day in 2020. Whittier Narrows Recreation Area, a popular spot for pedal boating, is one of 17 Los Angeles-area lakes where researchers are measuring cyanotoxin levels in the weeks around the busy Labor Day holiday.

SCCWRP has completed the first phase of sampling for a three-year study examining algal toxin levels in Los Angeles-area lakes surrounding the Labor Day holiday, when recreational use of the water bodies tends to jump – and also when algal bloom development generally soars.

The first sampling phase, completed in September at 17 recreational lakes, targeted the two weeks leading up to the holiday, and a few weeks after. Three types of cyanotoxins were measured: microcystins, anatoxin-a and cylindrospermopsin. Most sampling in the region to date has focused on microcystins only.

In subsequent sampling years, researchers will focus on a subset of high-priority lakes to better understand temporal dynamics and identify drivers of bloom formation. They also will examine HABs levels surrounding the Memorial Day holiday.

The sampling effort marked an early opportunity to test-drive elements of a proposed statewide strategy for monitoring harmful algal blooms (HABs) in freshwater environments. The strategy, which calls for significantly boosting capacity to track freshwater HABs in California, is expected to be finalized in early 2021.

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