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Noticing red, murky water at the beach? Here's why

Algae blooms.PNG
Posted at 1:46 PM, Aug 25, 2021

Some swimmers on the Central Coast are noticing red, murky waters at local beaches, which experts say shouldn't impact your weekend plans to hit the coast.

These conditions are expected for this time of year.

High concentrations of phyto-plankten, or tiny plant-like creatures in the ocean, can cause what's often described as a red tide.

Late summer and early fall are prime conditions for algae to grow rapidly and in high numbers.

Just like plants on land, different species take on different colors, like a dark green hue or become illuminated at night.

While this raises concerns for beachgoers, experts say there is no direct impact on humans.

"Some of these organisms and just a small fraction of the species do produce toxins, but we are less worried about direct contact with those toxins and more if organisms like mussels and clams eat the algae,” said Alexis pasulka, assistant professor at Cal Poly. “Those toxins get accumulated and so it can be dangerous to eat those organisms and so we do measure toxins and keep track of that.”

Cal Poly students regularly collect samples from the Cal Poly Pier and Morro Rock.

Student Elysa Romanini monitors algae levels and is seeing elevated concentrations in some areas.

"At the Morro Bay site this week, we saw super elevated concentrations, which also helped us realize that's probably the culprit of what we are seeing in Pismo as well,” Romanini said.

Because conditions and tides are constantly changing, blooms can last from days to months, but in general, a variety of blooms are expected to make appearances through the fall.