Harmful algal blooms (HABs) occur in coastal regions across the U.S., causing economic, ecological, and human health impacts. However, not much is known about the accumulation and persistence of HAB toxins and the impacts of these toxins on commercially relevant species along the U.S. Atlantic and Gulf coasts. This project will assess the persistence and food web transfer of HAB toxins in Chesapeake Bay, Virginia, and Barataria Bay, Louisiana.
Why We Care
Harmful Algal Blooms (HABs) are a growing concern in U.S. coastal regions, especially in areas like Chesapeake Bay, Virginia, and Barataria Bay, Louisiana. These estuaries are vital for American seafood competitiveness, as they produce the second and third highest seafood industry landings in the U.S. HABs also pose risks to human health; exposure to toxins can lead to skin, respiratory, and gastrointestinal issues, and in rare cases, death.
Even when HABs are not visible, toxins can persist in the environment and accumulate in economically valuable seafood species common to the Gulf and Atlantic coasts, such as oysters, shrimp, and blue crabs. We don’t fully understand how these toxins move through the food web or how long they persist in different parts of the ecosystem, such as sediments and water. This lack of information makes it difficult for health officials and resource managers to effectively predict and respond to HABs.
What We Are Doing
This project will assess the persistence and trophic transfer of four HAB toxins (domoic acid, okadaic acid, microcystins, and azaspiracids) in two estuaries: Chesapeake Bay, Virginia and Barataria Bay, Louisiana.
This project aims to:
- Map toxin distribution across the food web through quarterly food web surveys in the study regions.
- Assess toxin persistence, including how toxins move between the water and sediments and how environmental conditions such as temperature, salinity, pH, and light affect the breakdown and persistence of these toxins in seawater and sediments.
- Compare different routes of toxin exposure and impacts across species and trophic levels.
- Model trophic transfer of toxins to higher trophic level species and the potential for exposure to human consumers.
Benefits of Our Work
Public health and resource management will directly benefit from the project’s findings, which will ultimately support American seafood competitiveness and secure the economies and health of coastal communities. By identifying the drivers of toxin accumulation in seafood, health officials and resource managers will be better equipped to anticipate where and when HAB impacts might occur. This will enable them to focus monitoring efforts on specific toxin sources or food web components, and inform decisions on when fishing areas can be safely reopened after a bloom to minimize economic disruption to fisheries.
The project will produce dynamic food web models that illustrate the processes and mechanisms leading to toxin accumulation. The models will allow resource managers to identify which toxins pose the greatest risk, which seafood species are most affected, and which lower-level organisms contribute to toxin transfer, supporting the safety and marketability of U.S. seafood.
Juliette Smith of the Virginia Institute for Marine Science (VIMS) leads this project. Partners include the U.S. Geological Survey (USGS) Wetland and Aquatic Research Center; Louisiana State University Agricultural Center; Louisiana Department of Wildlife and Fisheries; Virginia Department of Health, Division of Shellfish Safety and Waterborne Hazards; and Florida Sea Grant.
The project is funded through the NCCOS Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Program and authorized under the Harmful Algal Bloom and Hypoxia Research and Control Act (33 U.S.C. §§ 4001 et seq.), which authorizes NOAA to detect and monitor harmful algae.