Citizen Science / Extension / Research / Sea Grant News

Engaging ocean-goers in harmful algal bloom monitoring

A volunteer collects a surf sample of phytoplankton that will be tested for the presence of any known toxic species. Credit: California Department of Public Health

A volunteer collects a surf sample of phytoplankton that will be tested for the presence of any known toxic species. Credit: California Department of Public Health

Patterns of harmful algal bloom formation are changing off California.

Harmful algal blooms (population explosions of toxin-producing algae) are no longer just coastal phenomena. In the last decade, “HABs” appear to have become more frequent, widespread and persistent in offshore waters, particularly in the Santa Barbara Channel.

To learn more about the distributions of these blooms and their implications for seafood safety, California Sea Grant Extension Specialist Carolynn Culver has partnered with Gregg Langlois of the California Department of Public Health (CDPH), Kristine Barsky of the California Department of Fish and Wildlife and Bahman Moezzi of CDPH’s Food and Drug Laboratory Branch to recruit a wider base of volunteers to help with the state’s biotoxin monitoring program.

The goal of the California Sea Grant-led pilot project, funded by CFR West, is to identify, train and organize a coordinated network of volunteers to monitor areas where blooms now appear to be forming more frequently.

“Monitoring needs to be expanded out to areas such as the northern and southern Channel Islands and boat-accessible fishing reefs,” Culver said.

Current CDPH volunteer efforts are focused on collecting water and seafood samples along the coast and around Catalina Island, Langlois said. If a biotoxin hotspot is detected, another round of sampling is conducted, targeting the collection of animals farther up the food chain, such as anchovy or crab, that are known to accumulate potentially dangerous toxins. 

Culver’s project is about identifying and training people who are already out on the water, or in it, to help monitor offshore areas that are not currently part of the state’s monitoring program. Volunteers for offshore monitoring include recreational and commercial fishermen, whale watching boat operators, marine education charter boat and camp leaders, research divers, and others from Santa Barbara to San Diego.

“The toxins that these algae produce are potentially lethal and need to be taken seriously,” Langlois said.

A scanning electron micrographic image of the algae that produce the toxin domoic acid. Credit: S. Bates/WHOI

A scanning electron micrograph of the algae that produce the toxin domoic acid, the causative agent of Amnesic Shellfish Poisoning. Credit:
S. Bates/WHOI

One of the most commonly detected natural toxins off Central and Southern California, domoic acid, can cause neurological damage known as Amnesic Shellfish Poisoning. The other toxin monitored regularly is the causative agent of Paralytic Shellfish Poisoning, which has been responsible for numerous illnesses and some deaths due to shellfish consumption. County-specific seafood health advisories are based on bioxtoxin testing results.

“Our team hopes to improve seafood safety of commercial and recreational fisheries in California by collecting data that could be incorporated directly with the state program,” Culver said.

With this in mind, she has worked with volunteers to modify sampling, communication and reporting protocols to be more easily integrated with CDPH and volunteer operations. She has also identified HAB outreach materials that would be most useful for educating fishing communities and seafood consumers.

In coming months, Culver will be analyzing data gathered last year to explore links between nearshore and offshore blooms. Intriguingly, some offshore blooms seem to develop and end without ever coming to shore, though a lack of data has made it difficult to understand how often this decoupling occurs.

If you frequent offshore waters from Santa Barbara to San Diego and are interested in volunteering, please send an email to For more information about the pilot offshore biotoxin monitoring project, contact Carolynn Culver, California Sea Grant Extension Program, Marine Science Institute, UC Santa Barbara at (805) 893-4530 or

For information about volunteer opportunities in other areas along the California coast with the CDPH shellfish and phytoplankton monitoring program send an email to

California Sea Grant is currently funding three research projects that examine the processes that may trigger or explain HAB formation in coastal waters of California. Below are summaries of these projects with contact information for the lead investigators.

Forecasting River Runoff Effects on Domoic Acid Production in Coastal California
R/CONT-221 Feb. 2013–Jan. 2014
Clarissa Anderson, UCSC, 831.459.3290,
Raphael Kudela, UCSC, 831.459.3290,
Christopher Edwards, UCSC, 831.459.3734,

California Sea Grant researcher Clarissa Anderson. Credit: UCSC

In Monterey Bay, harmful blooms of microalgae of the genus Pseudo-nitzschia (the algae that produce the neurotoxin domoic acid) are often associated with spring and early summer upwelling of macro-nutrients. Though less frequent, highly toxic blooms have also been observed after “first flush” storms in fall or early winter. It is believed that these blooms may be triggered by sudden changes in silicon and nitrate concentrations, associated with freshwater flows to the coast. Can this be proved? In this project, scientists are using field data collected before and after first flush storms, as well as other environmental and monitoring data, to parameterize a simple numerical model for predicting the rate of domoic acid production. The model assumes that the rate of domoic acid production is proportional to the biomass of Pseudo-nitzschia algae, multiplied by their growth rate. The proportionality constant assumes a primary nutrient limiting process (i.e., silicon limitation or nitrate limitation) and is a function of three “tunable” parameters. The main goal of this project is to back-solve (optimize) these three parameters using existing data, and to then check the “fit” using other existing or new data. When this is done, the scientists will have a zero-dimensional model for domoic acid production that they can continue to develop and ultimately couple to 3D circulation models. Domoic acid, which has caused marine mammal and seabird die-offs in Central California, can accumulate in seafood, causing Amnesic Shellfish Poisoning. New research suggests that chronic low-level exposure to the toxin may pose a health threat to vertebrates. Results from this project will further efforts to understand what causes these harmful algal blooms and to forecast their occurrence.

Submarine Groundwater Discharge in North Monterey Bay—The Fuel Sustaining the Algal Incubator
R/CONT-218 May 2012–Apr. 2014
Adina Paytan, UCSC, 831.459.1437,
John Ryan, Monterey Bay  Aquarium Research Institute, 831.775.1978,
Peter Swerzenski, USGS, 210.554.2420,

Certain kinds of harmful algal blooms in the northeastern portion of Monterey Bay form in late summer and early fall when upwelling is weak and surface waters are highly stratified, and hence favorable to mobile dinoflagellates. Though what fuels these blooms is not well documented, the region’s inner shelf circulation is believed to create retention zones within which nutrients and algae are accumulated. This theory, however, does not explain the persistence of dinoflagellate blooms during periods of intense upwelling, when shelf currents are not in a retention mode. The scientists leading this project theorize that submarine groundwater discharges may sustain these blooms during these periods by providing a continuous source of nutrients, metals, and dissolved organic carbon. The scientists have preliminary data consistent with the idea, and in this project will build on this preliminary work to more rigorously measure groundwater fluxes (using the geochemical tracers radium and radon) at six locations in the bay, two within the incubator zone and four controls outside it. A mass balance model for excess radium and radon will be used to quantify fresh groundwater and recirculated seawater inputs and constituent loads associated with this discharge to the bay. In addition, bioassay incubations with groundwater will be performed using in-situ “incubator” water and resident plankton species to identify nutrients, metal or other constituents that may be key to sustaining dinoflagellate growth.

Is C/N Decoupling Caused by Harmful Algal Blooms in Santa Monica Bay? 
R/CONT-209 Feb. 2010–Jan. 2014
Anita Leinweber, UCLA, 310.267.5165,
Rebecca Shipe, UCLA, 310.794.4903,

In the past, Santa Monica Bay has experienced harmful blooms of dinoflagellates in late summer and early fall during periods of low surface nitrate levels. The scientists leading this project had originally planned to sample the bay during one of these blooms to see if they could observe the “footprints” of foraging dinoflagellates. That is, they hoped to observe a draw down in nitrate levels beneath the surface mixed layer, associated with foraging, and a simultaneous draw down in dissolved organic carbon concentrations within the mixed layer, associated with cell growth in sun-lit waters. In this way, researchers had hoped to be able to explain the apparent decoupling of surface carbon and subsurface nitrate levels, as the byproduct of sub-surface dinoflagellate foraging. The ocean has not been cooperating, however, and in 2012 and 2013, late-summer blooms in Santa Monica Bay were dominated by another kind of algae, diatoms, which are not mobile and are typically associated with spring upwelling events. Scientists have speculated that ocean acidification may be creating conditions that favor diatoms over dinoflagellates.

Written by Christina Johnson,, 858-822-5334

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