Likely Algae Bloom In San Francisco Bay: Baykeepers

BERKELEY, CA — San Francisco Baykeeper investigated reports of reddish brown "tea colored" waters in the Berkeley Marina, and along the shorelines of Berkeley, Albany and Emeryville. Following a probe by a field science team and preliminary analyses, Baykeeper scientists suspect an outbreak of the algae Heterosigma akashiwo.

Last year, the same algae caused a red tide that spread across the Bay, resulting in a fish kill.

"It’s alarming to see an algae outbreak of this size in the Bay for the second year in a row," said Baykeeper science director Jon Rosenfield, PhD. "While it’s too early to tell how this harmful algae bloom will proceed, there’s not much that we can do to stop it once it has started. Prevention is the only cure."

Algae blooms are fueled by elevated levels of nitrogen and phosphorus, also called 'nutrient pollution," which comes primarily from the 37 regional wastewater treatment plants, which discharge partially treated sewage into the Bay.

According to Baykeeper, San Francisco Bay has some of the highest levels of nutrient pollution of any estuary in the world.

"The good news is we know how to reduce the nutrient pollution that fuels harmful algal blooms, and many of these solutions have multiple benefits," said Rosenfield. "We urge the San Francisco Bay Regional Water Quality Control Board to upgrade permits for Bay Area wastewater treatment facilities to dramatically reduce nutrient loads discharged into the Bay, and to encourage nature-based and other multi-benefit solutions."

Baykeeper recommends upgrading treatment facilities and building treatment wetlands which would capture sewage pollution before it enters the Bay.

The San Francisco Estuary Institute, the U.S. Geological Survey, other agencies and academic organizations, and Baykeeper are all investigating the algae bloom.

If you encounter water that looks or smells suspicious, report it to the pollution hotline.

Heterosigma akashiwo is not known to pose a risk to humans. However, it's wise to avoid discolored water and keep your dogs out of it.