SF Baykeeper Suspects Same Red Tide Algae as Last Year

An algae bloom in the San Francisco Bay near the Berkeley Marina on July 31, 2023. (Beth LaBerge/KQED)
Oakland, CA—San Francisco Baykeeper's field science team investigated reports to the organization's pollution hotline and confirmed reddish brown (“tea colored”) waters in the Berkeley marina, and subsequently along the shores of Emeryville, Berkeley, and Albany. Following preliminary analyses, Baykeeper scientists suspect this is likely caused by an outbreak of the algae Heterosigma akashiwo. Last year, a harmful bloom of the same algae caused a red tide that spread across the Bay, resulting in an unprecedented fish kill event.
“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."





My Water Quality: California Harmful Algal Blooms (HABs)
Algae blooms are fueled by elevated levels of nitrogen and phosphorus, also called “nutrient pollution.” San Francisco Bay has some of the highest levels of nutrient pollution of any estuary in the world. This pollution comes primarily from the region’s 37 wastewater treatment plants, which discharge treated sewage into the Bay.
“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," Rosenfield added. "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."
Wastewater treatment plants can be modernized to recycle wastewater, which would reduce nitrogen and phosphorus discharges in the process. Building treatment wetlands would capture sewage pollution before it enters the Bay. Restoring the Bay’s historic natural wetlands would absorb excess nitrogen and phosphorus from Bay waters.
Baykeeper is investigating this algae bloom and its causes in partnership with the San Francisco Estuary Institute, the U.S. Geological Survey, and other agencies and academic organizations. Baykeeper asks anyone who encounters water that looks or smells suspicious to report it to its pollution hotline.
The organism that likely forms this bloom is not known to pose a risk to humans. Regardless, Baykeeper advises caution when entering any water that is discolored.
Likely Algae Bloom Reported Along Central East Bay Shoreline | San Francisco Baykeeper
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Last Summer's Fish-Killing Algae Bloom Is Back in the Bay | KQED

A red tide that has left a light-brown sheen on the water along parts of the East Bay shoreline is the same type of toxic algae bloom that killed thousands of fish in the San Francisco Bay last summer, a local environmental group warned on Monday.
“We have confirmed with our partners that it’s the same species as last year,” Eileen White, executive officer of the San Francisco Regional Water Quality Control Board, said at a Monday afternoon press conference. She said the organism has so far been found in the bay waters near Emeryville, Albany, the Berkeley Marina, Richardson Bay and Belvedere Cove, as well as off the Marin County coast, near Muir Beach.
“The good news is we have not seen any marine animal deaths as a result of this algae bloom,” she said.
San Francisco Baykeeper’s pollution hotline lit up late last week with calls about the tea-colored water seen stretching from Emeryville to Albany, said Jon Rosenfield, the group’s senior scientist.
“Two years in a row is quite alarming,” he said, noting that it remained unclear how bad the bloom will get. “There’s really nothing that people can do to stop a bloom like this once it’s started. It just has to burn itself out.”
Red tides are fueled by elevated levels of nitrogen and phosphorus expelled into the water as a byproduct of treated sewage from wastewater treatment plants — leaving nutrients that algae love to nibble on. Such conditions can cause the algae to grow out of control and sometimes form a rust-colored hue.
Not every algal bloom is harmful, some can even be beneficial to marine habitats. But others produce deadly blooms — as did the one that emerged last August. That algae species, identified as Heterosigma akashiwo, and also believed to be the cause of the current bloom, killed an untold number fish over a matter of weeks, their rotting, fetid carcasses littered across Bay Area shorelines, including the banks of Lake Merritt.
The algae species emits a toxin that’s especially harmful to fish. It can also spur a biological reaction that depletes oxygen levels in the water, acerbating the marine death toll.
David Senn, a senior scientist at the San Francisco Estuary Institute, said that while it’s too soon to tell, the current bloom may be the result of algae from last year that lay dormant in sediment over the winter.
“It’s not all that surprising that we’re seeing a reemergence of this again this summer,” said Senn, whose group is using satellite imagery to track the bloom in real time.
Rosenfield, with SF Baykeeper, blames this and other recent harmful algal blooms on the region’s 37 wastewater plants that regularly discharge treated sewage into the bay. He said the regional water board has an opportunity next year to change permitting rules — when permits go up for renewal — to clamp down on the nutrient load the plants are allowed to release.
“San Francisco Bay has some of the highest levels of nutrient pollution of any estuary in the world,” he said. “The solution is to remove the fuel load, which means keeping those nutrients out of the bay waters.”
Although local wastewater treatment plants remove sewage, most do not filter out all the nutrients before discharging water back into the bay. Fixing the problem could cost at least $12 billion and maybe twice that much, according to Bay Area Clean Water Agencies, which represent local water districts.
White, with the regional water board, said some local wastewater plants are already redesigning their facilities to reduce the amount of nutrients released into the bay. But she said the push is not uniform and, although it could ramp up next year, there is currently no formal requirement for plant operators to reduce the nutrient loads that are discharged.
“Some of the wastewater agencies have already started planning, but knowing that it’s not like switching on a light switch, it’s going to take time to plan, design and construct,” said White, who formerly served as East Bay Municipal Utility District’s wastewater director.
Scientists also say red tides are likely to occur more often as the climate warms and raises water temperatures.
High nutrient loads and warming water is “like a one-two punch, and we really need to tackle both of the problems,” said Emily Jeffers, an attorney at the Center for Biological Diversity. “But the one that we can address more readily and more quickly is the nutrient loads from the wastewater-treatment facilities.”
Jeffers said she learned about the current algal bloom from her 8-year-old daughter, who attended summer camp at the Berkeley Marina last week.
“She said some kids might go in the water and that she didn’t think that was a good idea,” Jeffers said of her daughter. “I told her that was smart.”
Reddish-brown water due to an algae bloom can be seen in the Berkeley Marina on July 31, 2023. (Beth LaBerge/KQED)

An algae bloom in the San Francisco Bay near the Berkeley Marina on July 31, 2023. (Beth LaBerge/KQED)
Oakland, CA—San Francisco Baykeeper's field science team investigated reports to the organization's pollution hotline and confirmed reddish brown (“tea colored”) waters in the Berkeley marina, and subsequently along the shores of Emeryville, Berkeley, and Albany. Following preliminary analyses, Baykeeper scientists suspect this is likely caused by an outbreak of the algae Heterosigma akashiwo. Last year, a harmful bloom of the same algae caused a red tide that spread across the Bay, resulting in an unprecedented fish kill event.
“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."



My Water Quality: California Harmful Algal Blooms (HABs)
Algae blooms are fueled by elevated levels of nitrogen and phosphorus, also called “nutrient pollution.” San Francisco Bay has some of the highest levels of nutrient pollution of any estuary in the world. This pollution comes primarily from the region’s 37 wastewater treatment plants, which discharge treated sewage into the Bay.
“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," Rosenfield added. "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."
Wastewater treatment plants can be modernized to recycle wastewater, which would reduce nitrogen and phosphorus discharges in the process. Building treatment wetlands would capture sewage pollution before it enters the Bay. Restoring the Bay’s historic natural wetlands would absorb excess nitrogen and phosphorus from Bay waters.
Baykeeper is investigating this algae bloom and its causes in partnership with the San Francisco Estuary Institute, the U.S. Geological Survey, and other agencies and academic organizations. Baykeeper asks anyone who encounters water that looks or smells suspicious to report it to its pollution hotline.
The organism that likely forms this bloom is not known to pose a risk to humans. Regardless, Baykeeper advises caution when entering any water that is discolored.
Likely Algae Bloom Reported Along Central East Bay Shoreline | San Francisco Baykeeper
************************************
Last Summer's Fish-Killing Algae Bloom Is Back in the Bay | KQED

A red tide that has left a light-brown sheen on the water along parts of the East Bay shoreline is the same type of toxic algae bloom that killed thousands of fish in the San Francisco Bay last summer, a local environmental group warned on Monday.
“We have confirmed with our partners that it’s the same species as last year,” Eileen White, executive officer of the San Francisco Regional Water Quality Control Board, said at a Monday afternoon press conference. She said the organism has so far been found in the bay waters near Emeryville, Albany, the Berkeley Marina, Richardson Bay and Belvedere Cove, as well as off the Marin County coast, near Muir Beach.
“The good news is we have not seen any marine animal deaths as a result of this algae bloom,” she said.
San Francisco Baykeeper’s pollution hotline lit up late last week with calls about the tea-colored water seen stretching from Emeryville to Albany, said Jon Rosenfield, the group’s senior scientist.
“Two years in a row is quite alarming,” he said, noting that it remained unclear how bad the bloom will get. “There’s really nothing that people can do to stop a bloom like this once it’s started. It just has to burn itself out.”
Red tides are fueled by elevated levels of nitrogen and phosphorus expelled into the water as a byproduct of treated sewage from wastewater treatment plants — leaving nutrients that algae love to nibble on. Such conditions can cause the algae to grow out of control and sometimes form a rust-colored hue.
Not every algal bloom is harmful, some can even be beneficial to marine habitats. But others produce deadly blooms — as did the one that emerged last August. That algae species, identified as Heterosigma akashiwo, and also believed to be the cause of the current bloom, killed an untold number fish over a matter of weeks, their rotting, fetid carcasses littered across Bay Area shorelines, including the banks of Lake Merritt.
The algae species emits a toxin that’s especially harmful to fish. It can also spur a biological reaction that depletes oxygen levels in the water, acerbating the marine death toll.
David Senn, a senior scientist at the San Francisco Estuary Institute, said that while it’s too soon to tell, the current bloom may be the result of algae from last year that lay dormant in sediment over the winter.
“It’s not all that surprising that we’re seeing a reemergence of this again this summer,” said Senn, whose group is using satellite imagery to track the bloom in real time.
Rosenfield, with SF Baykeeper, blames this and other recent harmful algal blooms on the region’s 37 wastewater plants that regularly discharge treated sewage into the bay. He said the regional water board has an opportunity next year to change permitting rules — when permits go up for renewal — to clamp down on the nutrient load the plants are allowed to release.
“San Francisco Bay has some of the highest levels of nutrient pollution of any estuary in the world,” he said. “The solution is to remove the fuel load, which means keeping those nutrients out of the bay waters.”
Although local wastewater treatment plants remove sewage, most do not filter out all the nutrients before discharging water back into the bay. Fixing the problem could cost at least $12 billion and maybe twice that much, according to Bay Area Clean Water Agencies, which represent local water districts.
White, with the regional water board, said some local wastewater plants are already redesigning their facilities to reduce the amount of nutrients released into the bay. But she said the push is not uniform and, although it could ramp up next year, there is currently no formal requirement for plant operators to reduce the nutrient loads that are discharged.
“Some of the wastewater agencies have already started planning, but knowing that it’s not like switching on a light switch, it’s going to take time to plan, design and construct,” said White, who formerly served as East Bay Municipal Utility District’s wastewater director.
Scientists also say red tides are likely to occur more often as the climate warms and raises water temperatures.
High nutrient loads and warming water is “like a one-two punch, and we really need to tackle both of the problems,” said Emily Jeffers, an attorney at the Center for Biological Diversity. “But the one that we can address more readily and more quickly is the nutrient loads from the wastewater-treatment facilities.”
Jeffers said she learned about the current algal bloom from her 8-year-old daughter, who attended summer camp at the Berkeley Marina last week.
“She said some kids might go in the water and that she didn’t think that was a good idea,” Jeffers said of her daughter. “I told her that was smart.”
Reddish-brown water due to an algae bloom can be seen in the Berkeley Marina on July 31, 2023. (Beth LaBerge/KQED)