After staining the East Bay shoreline a dismal tea brown, the toxic algae bloom that wreaked havoc in the San Francisco Bay in 2022 has reappeared, posing renewed threats to marine life. Researchers believe that the same organisms responsible for last year’s bloom may have lain dormant over the winter, only to resurface as water temperatures rise with the summer sun.

Although no dead fish have been reported yet, last summer's bloom took between six and seven weeks to culminate in a large-scale die-off. The toxic algae bloom can be lethal to marine life, but is not known to be directly harmful to humans, however, it is still best to avoid contact with the discolored water as a precautionary measure per NBC Bay Area.

Worryingly, this year's bloom seems "initially more widespread than the initial bloom was last year," said Jon Rosenfield, who has been closely monitoring the situation alongside the San Francisco Baykeeper team according to the San Francisco Chronicle. David Senn, senior scientist at the San Francisco Estuary Institute, acknowledged the uncertainty surrounding the bloom's trajectory, but emphasized the importance of prompt action and the potential for a range of outcomes.

The toxic algae bloom, which has largely been fueled by nutrients from treated wastewater released from the Bay Area's 37 sewage plants, takes advantage of elevated levels of nitrogen and phosphorus to grow in dangerous concentrations. With this in mind, Baykeeper researchers have urged the San Francisco Bay Regional Water Quality Control Board to upgrade permits for local wastewater treatment facilities to dramatically reduce nutrient loads discharged into the bay.