Home > Explore Projects > RAPDALERT – Rapid Analysis of Pseudo-nitzschia and Domoic Acid, Locating Events in Near–Real Time
NCCOS Project

RAPDALERT – Rapid Analysis of Pseudo-nitzschia and Domoic Acid, Locating Events in Near–Real Time

This project began in January 2005 and was completed in December 2010

Through this pilot project in the coastal waters of Southern California, we demonstrated the effectiveness of adding emerging technologies to harmful algal bloom monitoring programs that focus on toxic blooms of Pseudo-nitzschia. Specifically, we improved the detection capabilities of an existing program by enhancing it with a network of in situ sensors, state-of-the-art remote sensing, and cutting-edge species identification and algal neurotoxin (i.e., domoic acid) quantification methods.

Why We Care
Diatoms of the genus Pseudo-nitzschia are recognized worldwide as potential producers of domoic acid, a water-soluble neurotoxin that accumulates in filter-feeding organisms, most notably shellfish and planktivorous fish. People who eat seafood contaminated with domoic acid may experience Amnesic Shellfish Poisoning, whose symptoms include vomiting, confusion, memory loss, coma, or even death.

In the United States, domoic acid is recognized as a recurring human health issue for Dungeness crab, razor clams, and other shellfish along the U.S. West Coast. Domoic acid has also resulted in large-scale poisoning of West Coast marine vertebrate populations, including sea lions, dolphins, and sea birds. In Monterey Bay, California in 1991, hundreds of brown pelicans, cormorants, and marine mammals were observed exhibiting unusual behavior and many died. Autopsies revealed domoic acid poisoning from feeding on domoic acid–contaminated anchovies and other fish.

What We Did
Since the 1991 Monterey Bay bloom event, Pseudo-nitzschia has become the focus of considerable research in California. Toxic Pseudo-nitzschia has also been documented in the Gulf of Mexico, Gulf of Maine, and other parts of the U.S. The lack of easy species identification and the lack of a correlation between species cell abundance and toxin concentration are two scientific issues that confound our understanding and management of toxic Pseudo-nitzschia events. As prevention is not yet a realistic goal, we focused on the development of an effective early warning system to detect toxic Pseudo-nitzschia species at sub-bloom abundances. Surveillance and early detection are the only reasonable ways to currently mitigate the effects of harmful algal blooms.

This project added innovative in situ sensor networking technology, state-of-the-art remote sensing, and cutting-edge species identification and domoic acid quantification methods to an intensive harmful algal bloom monitoring program off the southern California coast. The project served as a template for demonstrating that shifting much of the burden of harmful algal bloom monitoring to an automated system can provide early warning of impending blooms, while minimizing expensive field-based sampling and lab-based testing. The resulting information advanced our understanding and ability to predict harmful algal bloom events.

Use of the in situ sensor and remote sensing data, in conjunction with field sampling, enabled tracking of the inception, proliferation, advection, and decline of bloom events in real-time. In turn, this provided managers with the necessary information to make informed decisions on when and where to direct their staff in the field to efficiently increase their efforts. The in situ sensor network (a network of 10 stationary nodes and an autonomous glider) provided synoptic coverage of the study area, within-network data collection and communication, and, ultimately, sensor-actuated sampling and sample retrieval. Coupled with information from remote sensing, the network facilitated real-time data visualization, enabling a rapid response by agencies to emerging events. Integration of sensor information provided unprecedented spatial and temporal resolution of relevant parameters on scales sufficient to resolve algal bloom dynamics.

The project was able to achieve the transfer of emerging technologies for bloom monitoring, the identification of Pseudo-nitzschia species and concentrations of domoic acid through the establishment of partnerships between scientists with harmful algal bloom expertise and agencies charged with water quality monitoring. Stakeholder meetings were held to assess the need for new approaches within agencies and to facilitate the transfer of new technology into the hands of end-users.

The project, funded through the NCCOS Monitoring and Event Response for Harmful Algal Blooms (MERHAB) program, was led by Dr. David Caron of the University of Southern California. Focusing on the Southern California Bight, the lead partner management agency was the Southern California Coastal Water Research Project (SCCWRP). Some specific accomplishments included:

  • Statewide California Harmful Algal Bloom Monitoring and Alert Program (HABMAP) workshops
    Two regional workshops for Harmful Algal Blooms in California Coastal Waters were completed. The workshops were jointly organized by RAPDALERT and other NCCOS harmful algal bloom projects, NOAA, and SCCWRP.
  • King Harbor (Redondo Beach) and Marina Del Rey harbor sensor networks partnership
    RAPDALERT used the National Science Foundation Center for Embedded Network Sensing small-scale sensor network within the highly urbanized harbors of Santa Monica Bay along with the privately funded Marina Del Rey harbor sensor network incorporating the information streaming from the sensor networks into the larger data stream coming from the RAPDALERT sensor network and other collaborative programs.
  • West Basin Municipal Water District (WBMWD) and Long Beach Water Department
    RAPDALERT investigators collaborated with WBMWD to investigate the potential impact of harmful algal blooms on seawater desalination operations anticipated within the Southern California region. RAPDALERT also conducted monitoring studies of pilot desalination operations with Long Beach Water Department providing a degree of early warning to RAPDALERT of the presence of harmful algal blooms as well to the desalination plants. One component was the deployment of two, large monitoring buoys off the coasts of the cities of Redondo Beach and El Segundo, both within Santa Monica Bay. The information streaming from the buoys was incorporated into the larger data stream coming from RAPDALERT and other collaborative programs.
  • Monitoring of harmful algal blooms in waters off Marine Corps Base Camp Pendleton
    RAPDALERT investigators performed phytoplankton taxonomic analysis, chlorophyll concentration analyses and phytoplankton toxin analyses (domoic acid, saxitoxins) in conjunction with ECORP Consulting, Inc. as part of the Camp Pendleton Nearshore Biological Baseline Assessment improving overall monitoring coverage within the region.
  • Collaborated with bird and marine mammal regional rescue centers that deal with bird and mammal stranding and illness during toxic bloom outbreaks.
  • Enacted a Regional Oceanic Modeling System (ROMS) for harmful algal blooms
    RAPDALERT investigators initiated an informal regional working group in the greater Los Angeles region to formulate and test models to predict harmful algal bloom formation and fates. RAPALERT provided much of the biological data for enhancing the mostly physical ROMS.
  • Provided the California Department of Health Services with Pseudo-nitzschia abundance information for use in their monthly biotoxin publication.

Benefits of Our Work and Next Steps
This project enabled coastal monitoring programs to incorporate new, cost-effective monitoring methods and to detect, quantify, and predict domoic acid and Pseudo-nitzschia species. These enhancements took monitoring to a new level, providing insights into the factors that promote the growth of Pseudo-nitzschia and production of domoic acid.

In the long term, RAPDALERT improved coordination with existing West Coast harmful algal bloom programs focused on Pseudo-nitzschia. The project served as a template for future remote sensing and sampling strategies and provided improved methodology for sample analysis. Moreover, the sensor network served as a blueprint for future, fine-scale Pseudo-nitzschia sensing and sampling platforms around the U.S. NCCOS will use the RAPDALERT project as a stepping stone for a future operational Southern California Bight harmful algal bloom forecast system.

Additional Resources

Click to expand resource list(s).

Products, Datasets & Reports

Peer-Reviewed Publications

Related Links

Explore Similar Projects
No posts found.


NCCOS delivers ecosystem science solutions for stewardship of the nation’s ocean and coastal resources to sustain thriving coastal communities and economies.

Stay Connected

Sign up for our quarterly newsletter or view our archives.

Follow us on Social

Listen to our Podcast

Check our our new podcast "Coastal Conversations"