Award: OCE-1840381

The Woods Hole Center for Oceans and Human Health (WHCOHH) addressed fundamental issues of the dynamics of harmful algal blooms (HABs) - biological events with significant human health consequences in the coastal ocean, including offshore, coastal and estuarine systems. The Centers research employed focused and complementary biological, hydrographic, climatic, and modeling studies of key habitats and processes, and considered critical yet largely unaddressed toxicological mechanisms. The latter addressed consequences of sub-acute exposure, especially during development, with potentially pervasive and pernicious effects in exposed populations. Each Project and the Administrative Core conveyed research findings in primary publications and presentations at national and international meetings, as well as to the general public. The research in each Project contributed to the training and professional development of multiple students. Project 1: Physiological studies of Alexandrium catenella produced a conceptual model for bloom initiation that quantifies temperature regulation of dormancy that explains a long-term decreasing trend in the severity of toxic events in the Gulf of Maine, in contrast to an increasing trend in shallow estuaries. These studies were critical to forecasts of climate-driven, Alexandrium blooms in the Alaskan Arctic where the largest cyst seedbed for this species globally was found. The findings have major implications for communities dependent on marine food resources that are vectors for toxins. Substantial progress was made on a regional HAB observing system and data portal that are providing in situ data on bloom and toxin dynamics. These were used to refine a numerical model of A. catenella population dynamics in the Nauset Marsh System and to improve a large-scale model for HAB forecasts in the Gulf of Maine. Project 2: Observational and modeling studies identified key factors contributing to the evolving threat from domoic acid (DA) in the Gulf. The predominance of a particularly toxic Pseudo-nitzschia species novel to the region, P. australis, was found to likely result from introduction of cells from source waters on the Scotian Shelf in 2016. Interestingly, P. australis has persisted in the region ever since, but DA levels in shellfish have declined, suggesting a changing relationship between P. australis abundance and shellfish toxicityperhaps due to a changing nutrient environment. Climate projections based on the temperature dependence of P. australis indicate its blooms are likely to shift later in the fall and persist through winter into spring, and the Pseudo-nitzschia community is likely to be comprised of warmer adapted species. 25-year model hindcasts (1994-2018) and climate projections (2073-2097) of A. catenella were developed, along with a 40-year record of observed toxicity from shellfish monitoring, to assess interannual variability and climate-driven trends. Studies in Project 1 and Project 2 together with Institutional infrastructure enhancements, including expanding workforce capacity to maintain ocean observing systems, enabled sharing of real-time data and analyses through WHOI HABhub. This is a data portal for region-scale assimilation of data to help resource managers and others stay informed on the status of HABs and toxins. These platforms serve researchers through the US National Harmful Algal Bloom Observing Network. Project 3: Studies of early life exposure to DA in the zebrafish embryo model identified a developmental window of susceptibility to DA-induced neurodevelopmental effects and mechanisms involving altered gene expression and disrupted myelination. Additional studies showed behavioral deficits linked to the altered myelination and that the myelin defects were associated with the loss of specific reticulospinal neurons. Experiments on developmental effects of saxitoxin exposure revealed altered branching of primary motor neurons. Results suggested that cell-cell and cell-extracellular matrix (ECM) interactions were affected by saxitoxin. Additional studies to assess mechanisms underlying the developmental neurotoxicity of PCBs that co-occur with HABs revealed transcriptomic and epitranscriptomic effects, altered DNA methylation, and behavioral changes. A key result was the identification of a novel cellular mechanism of developmental neurotoxicity of non-ortho PCBs. Community Engagement Core (CEC): The WHCOHH-CEC together with CECs from other OHH centers developed a strategic framework for OHH researchers in coordinating partners, purpose, activities, and approaches in their work with communities. The CEC convened the annual Gulf of Maine HAB Symposium to engage stakeholders and improve understanding of HABs, and also worked to develop WHOI HABhub. To improve ocean literacy for K-12, educational activities based on WHCOHH research were developed, and included adaptations for visually impaired students. CEC also participated in education and outreach in underserved school districts and contributed to engagement with public health and medical communities through podcasts and webinars. Administrative Core: Regular meetings involved exchange of ideas and data among all Center members. The Director co-authored (with Projects 1 and 3 leaders) a major review on ocean pollution and health, organized an OHH session at AAAS 2022, presented on OHH at the Consortium of Universities for Global Health, Society of Toxicology, Ocean Sciences, the Ocean Visions Summit, and the UN Ocean Decade. Review involved Internal, External and CEC Advisory Committees. Last Modified: 12/10/2024 Submitted by: JohnJStegeman