Cyanobacterial blooms and toxins in high-latitude estuaries: an emerging threat with potential impacts on subsistence resources we propose a targeted study of cyanobacterial blooms and their toxins in…

Columbia University received a $1,868,656 cooperative agreement from the National Oceanic and Atmospheric Administration (NOAA) under the Center for Sponsored Coastal Ocean Research Coastal Ocean Program (CFDA 11.478), effective June 1, 2025 through May 31, 2028. The award supports a targeted research study investigating cyanobacterial harmful algal blooms (HABs) and associated toxins in Kotzebue Sound, Alaska, an Arctic estuary experiencing unprecedented annual blooms since 2008. Through in situ sampling, remote sensing, and laboratory experiments, the project will identify environmental drivers of bloom formation and toxin production, with particular emphasis on temperature and nutrient availability as factors promoting growth under climate warming conditions.

The research directly addresses community concerns regarding impacts on subsistence food resources and will produce scientific findings and management tools to enable resource managers and local stakeholders to understand immediate and long-term consequences of these emerging blooms. Deliverables will include environmental baseline data, remote sensing analyses, experimental results on bloom drivers, and actionable guidance for managers responding to this novel threat in high-latitude waters. This multi-year award exemplifies NOAA's Competitive Research Program focus on producing peer-reviewed, collaborative science that supports coastal management and policy decisions while protecting ecosystem health and community economic vitality.

Cyanobacterial blooms and toxins in high-latitude estuaries: an emerging threat with potential impacts on subsistence resources we propose a targeted study of cyanobacterial blooms and their toxins in high-latitude estuaries, using kotzebue sound, alaska as our study site. Cyanobacterial harmful algal blooms (habs) are frequently associated with high temperatures and high nutrient availability, suggesting that they will become more common due to climate warming and ongoing eutrophication of many aquatic environments. In this context, the arctic is warming faster than other regions of the planet and previously unprecedented cyanobacterial blooms have been observed annually in AUG/sept in kotzebue sound, alaska since 2008. Kotzebue sound is an embayment of the chukchi sea straddling the arctic circle, receiving inflow from multiple arctic rivers. Taxonomic identification of cyanobacteria from blooms and the presence of cyanobacterial toxins in kotzebue sound were verified in samples from 2009-2010, and more recent occurrences are consistent with satellite observations of surface algal blooms annually in AUG/sept. Visual and microscopic observations, and in situ instruments indicate that these recurring blooms are cyanobacterial. The blooms and their toxins are of great concern to the local community because of the potential impacts on subsistence foods, and because indigenous knowledge indicates that such events did not previously occur. However, at this time, managers cannot respond to the most fundamental questions from the local community related to the immediate, and long-term impacts of these blooms. Through in situ sampling, remote sensing, and lab experiments, this project will address key questions posed by the local community and managers. To investigate environmental drivers of these blooms, especially the potential importance of temperature and nutrients, this project will determine: 1) how do environmental variables promote the growth and in-situ abundance of cyanobacteria in kotzebue sound? To address concerns about possible cyanotoxins in subsistence foods, the project will answer: 2) what levels of cyanotoxins are found in water, fish, and shellfish, and do toxin levels relate to cyanobacterial abundance and environmental variables? Additional important project goals with direct management relevance include: 3) testing and validating remote-sensing HAB algorithms to assess their management utility in high-latitude coastal waters, and 4) building local capacity and communicating results to local communities and managers. This is a 3-year project with field sampling planned for each of the first 2 years of the project, leveraging instrumentation and facilities (an imaging flow cytometer, and a field lab van) recently acquired by the native village of kotzebue. The final year of the project will focus on completing sample processing, data management, analysis and synthesis, and dissemination and outreach of project outcomes. The project work plan was developed through close communication with local managers and the local community, and focuses specifically on sampling in kotzebue sound. Nevertheless, cyanobacterial blooms are likely more widespread in high-latitude estuaries, for which kotzebue sound serves as a model system. Thus, the proposed project is directly relevant to the following named ecohab FY2024 priorities: a) the local and regional drivers that govern bloom initiation, maintenance, and toxin production; b) the presence of HAB toxins in subsistence resources, and c) the effects of environmental or anthropogenic changes on habs and their impacts.