Map of planned cruise tracks of research vessels carrying an IFCB during the summer of 2025.
This summer, AOOS deployed its two Imaging FlowCytoBots (IFCBs) on a variety of research vessels as they conducted cruises in the waters of Alaska. These IFCBs are connected to the flow-through seawater system of the vessels, sample 5 mL of seawater in about 20 minutes, and take images of individual particles in the water. When the IFCB is connected to the shipboard internet, these images are uploaded in near-real time and can be examined to determine whether any harmful algal bloom (HAB) species were detected. The IFCBs have been deployed on four different vessels this summer, covering a large portion of the waters around Alaska.
The IFCB deployments allowed us to get snapshots of the phytoplankton community across large distances and throughout the summer. It has also given us many opportunities to look for HAB species, such as Alexandrium spp., which can produce a suite of toxins called paralytic shellfish toxins. During an Alexandrium bloom, zooplankton, fish, and filter-feeding invertebrates ingest toxic Alexandrium cells and concentrate the toxins in their tissues. These organisms are then eaten by other animals in the food web, and if toxic food items are ingested by humans in large enough quantities, it can lead to paralytic shellfish poisoning (PSP).
Map of some of the locations of samples taken by the IFCB on the R/V Sikuliaq on August 2-3. The colors of the circles show the cell density (cells per liter) of Alexandrium cells in the samples. Densities over 1,000 cells per liter are considered high enough to potentially produce a toxic event.
So far, the IFCBs have detected two Alexandrium blooms in the Southeast Bering Sea: one on July 14, about 160 miles east of the Pribilof Islands, and another on August 2–3, right around St. Paul Island. In both cases, when these blooms were detected, an advisory was drafted and sent to key regional contacts and the State of Alaska Department of Health to make them aware of the situation. The goal is to minimize the likelihood and severity of PSP cases, and to provide a possible explanation for unusual mortality events of wildlife (as happened in 2024).
In addition, the IFCB data are uploaded to publicly available online dashboards and archived for future use. They provide a complete and quantitative assessment of the phytoplankton community, which can be of great interest for ecological and fisheries-related questions.
Below are the links to the dashboards where you can visualize the data being collected:
- R/V Tiglax (June 13 – 22): https://habon-ifcb.whoi.edu/aoos_Tiglax0625
- R/V Norseman II (July 2 – 17): https://habon-ifcb.whoi.edu/aoos_Norseman0725
- R/V Sikuliaq (June 25 – ongoing): https://habon-ifcb.whoi.edu/aoos_Sikuliaq2025
- R/V Nanuq (July 24 – September 10): data not yet uploaded
- R/V Tiglax (September 15 – 25): upcoming
Finally, the Alaska Harmful Algal Bloom Network hosted a contest to give names to the two AOOS IFCBs. The final voting results determined that the two IFCBs will be named C3P-Flow and Sir Scans-a-Lot. Stay tuned for the future adventures of C3P-Flow and Sir Scans-a-Lot!
For more information on IFCBs, please visit the Alaska Harmful Algal Bloom Network website.
CONTACT: Thomas Farrugia, farrugia@aoos.org
Example of the dashboard showing one of the samples with elevated levels of Alexandrium near St Paul on August 3, 2025. The mosaic of images on the left shows 14 Alexandrium cells (large dark circles). The map on the right shows all the locations sampled by the IFCB on the R/V Sikuliaq June 25 – September 3, 2025.