Timeline and structure of rapid detection and risk communication information flow from shipboard HAB detection using an Imaging FlowCytobot (IFCB) to the regional coastal response (Fachon et al. 2024 Limnology and Oceanography Letters).

During summer 2022, a research cruise detected a massive bloom of the harmful algae, Alexandrium catenella, that spread at least 600 kilometers (~370 miles) from the northern Bering Sea to the southern Chukchi Sea. The new technologies used to track this harmful algal bloom (HAB) event and real-time collaborative communication with western Alaska entities to alert and inform remote coastal communities in the Bering Strait region are detailed in a new publication, “Tracking a large-scale and highly toxic Arctic algal bloom: rapid detection and risk communication,” in Limnology and Oceanography Letters.  

Alexandrium catenella produces neurotoxins called paralytic shellfish toxins (PSTs). These toxins can accumulate in organisms that consume the algae, and the toxins can be transferred through the marine food web causing illness or mortality of marine animals and can cause Paralytic Shellfish Poisoning (PSP) in people who eat contaminated seafoods. During this 2022 HAB event, Alexandrium cell density exceeded 174,000 cells per liter - the highest Alexandrium cell density ever observed in Arctic waters. Cell densities exceeding 1,000 cells per liter are considered dangerous.

While commercial seafood products are monitored for HAB toxins to ensure consumer safety, coastal communities in western and northern Alaska often rely on subsistence seafoods that are not regularly tested. The authors hope this research will bring attention to the issues the Bering Strait region is facing, and motivate more robust testing and monitoring. They note that continued warming may shift the Pacific Arctic towards more favorable conditions for Alexandrium catenella blooms, and that comprehensive monitoring and response resources will be essential in mitigating the impacts of future HAB events. 

The collaborative communications between scientists and HAB-affected communities during the 2022 HAB event demonstrated that researchers and western and northern Alaskan coastal communities benefit by directly working together on emerging threats to marine wildlife resources and human health. To advance such capacity sharing, the NCCOS HAB Event Response Program awarded funding during summer 2023 for the collection of real-time HAB data in the Bering Strait region and proactive, region-specific HAB outreach and response planning to inform and prepare Bering Strait communities for HAB events.   

This study was supported in part by the NCCOS Ecology & Oceanography of Harmful Algal Blooms (ECOHAB) project Trophic Transfer and Effects of HAB Toxins in Alaskan Marine Food Webs, led by Don Anderson at WHOI and Kathi Lefebvre at NOAA’s Northwest Fisheries Science Center (NWFSC). 

ECOHAB is a peer-reviewed, national, competitive program that funds research to advance understanding of the causes and impacts of HABs. ECOHAB research informs management of coastal resources to reduce HAB impacts and future threats.

Citation: Fachon, E., Pickart, R.S., Sheffield, G., Pate, E., Pathare, M., Brosnahan, M.L., Muhlbach, E., Horn, K., Spada N.N., Rajagopalan, A., Lin, P., McRaven, L.T., Lago, L.S., Huang, J., Bahr, F., Stockwell, D.A., Hubbard, K.A., Farrugia, T.J., Lefebvre, K.A., Anderson, D.M., 2024. Tracking a large-scale and highly toxic Arctic algal bloom: rapid detection and risk communication. Limnology and Oceanography Letters. https://doi.org/10.1002/lol2.10421

Related news: 

• WHOI Press Release: The Detection of a Massive Harmful Algal Bloom in the Arctic Prompts Real-Time Advisories to Western Alaskan Communities
• Collaborative Efforts Lead to Proactive Harmful Algal Bloom Risk Advisories in Alaska’s Bering Strait Region
• Warming oceans are pushing harmful algal blooms into polar waters