Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Standard station CTD profiles measurements (down casts) with water sampling (up casts);

Calculations of the concentration (cells/Liter) of Alexandrium catenella, formerly A. fundyense, were completed using MS Excel. The spreadsheet used inputs of the original volume sieved at sea (usually 2 Liters), the volume re-suspended into formalin and then methanol (usually 14ml), and the volume of the plankton concentrate filtered for the molecular probe assay (usually 7ml,  or less volume if during a significant bloom), and the number of labeled cells observed on that filter.

"Whole Cell" preserved samples. For the “Whole Cell” A. catenella water samples collected during the surveys, 2 Liters of seawater were drained from Niskin bottles into pre-rinsed bottles and sieved thru 20µm Nitex. The concentrated particulate material retained on the sieve was backwashed with filtered seawater (<15µm) into 15ml centrifuge tubes to a final volume of 14ml and preserved with formalin to a final concentration of 5%. After storage at 4oC for no longer than 36 hours, the tubes were centrifuged for 5 min (5000 x g), formalin was removed by aspiration leaving the pellet, replaced with 100% cold methanol, and stored at -20C for later analysis.

Enumeratio"n of the WC samples followed the methods developed by Anderson et al (2005a) using a species-specific oligonucleotide probe (NA-1) conjugated to a Cy3 fluorochrome and visualized with epi-fluorescence microscopy.

“Live" Count samples. To obtain quick estimates of Alexandrium sp. concentrations while at sea, 10 L of seawater from a surface 10L Niskin bottle was sieved and concentrated to 14ml.   A 1ml aliquot of the concentrate was loaded into a Sedgewick- Rafter counting chamber and enumerated using standard light microscopy.

Alexandrium catenella and Pseudo-nitzschia spp. threaten human health through their production of potent neurotoxins that respectively cause Paralytic Shellfish Poisoning and Amnesic Shellfish Poisoning. Both are widespread across coastal waters of the U.S. and globally. Environmental factors alter marine ecosystems in many unanticipated ways, and a major concern is that the occurrence of these harmful algal blooms (HABs) and their concomitant human health impacts will grow. This project addresses key uncertainties regarding the impact of environmental variability on the timing and severity of HABs through detailed biological and ecological study of Alexandrium and Pseudo-nitzschia blooms within the Gulf of Maine (GOM). The GOM is an ideal system because of the long history of regional HAB issues and associated groundbreaking research by WHCOHH. Comprehensive studies of bloom physiology, toxicity, and oceanographic drivers have led to construction of coupled physical-biological models that have improved our understanding of key HAB dynamics and set the stage for continued interdisciplinary investigation of mechanisms at the cellular-to-GOM scale that are relevant to human exposure and health. In particular, the physiological responses of these HABs — growth, toxicity, and life cycle transitions — to shifting environmental conditions remain uncertain. We hypothesize that long-term trends in HAB risks in the GOM are inherently linked to physiological processes and toxin dynamics that are driven by ecological stimuli. This project’s aims are designed to illuminate the role of life cycle dynamics and cellular physiology in determining the occurrence of Alexandrium and Pseudo-nitzschia blooms. We apply a wide variety of innovative approaches for study of natural populations in situ, leveraging a unique region-scale HAB observing system (HABON-NE). Aims 1 and 2 focus on A. catenella and seek to characterize cyst dormancy cycles, cyst formation, and subsequent bloom termination. These aims build upon prior successful approaches and models from study of inshore systems, asking the question if open water populations of the GOM are governed by similar dynamics. Aim 3 investigates the physiology underlying the emerging bloom dynamics of Pseudo-nitzschia in the GOM with in situ physiological observation coupled with targeted metatranscriptomics. Through the direct assessment of life cycle processes and physiology of HABs in the GOM, the results from this work will be directly applicable to the successful integration of physiology into models (Project 2) and inform estimates of potential risk for human exposure to HAB toxins (Project 3).

Overall Abstract:
The Woods Hole Center for Oceans and Human Health (WHCOHH) will comprise a strong and integrated set of research projects using novel in situ sampling technologies and modeling approaches building on prior research to address how environmental factors influence harmful algal bloom (HAB) dynamics and human exposure to HAB toxins, a serious and global human health threat. The overall objective is to protect public health through enhanced understanding of how oceanic processes affect the intensity and distribution of toxin-producing HABs and to understand the potential health risks from exposure even to low levels of their potent neurotoxins, especially during susceptible stages of life. The Center will focus on two key HAB taxa: Alexandrium catenella, which produces the saxitoxins responsible for paralytic shellfish poisoning (PSP), and Pseudo-nitzschia spp., which produce domoic acid responsible for amnesic shellfish poisoning (ASP) syndrome, both are expanding geographically. Novel, targeted, efficient, and data-rich sampling approaches developed by the applicants and applied in situ in natural settings have revealed new controls of A. catenella population dynamics, and have identified possible new environmental links regarding toxic Pseudo-nitzschia species. Project 1 will examine further the physiological and environmental variables affecting these HABs, which may underlie population adaptation in different habitats and different environmental regimes. Project 2 will incorporate these new and fundamental insights on bloom regulation into coupled population models to predict HAB events, a key step toward being able to quantify future risks from this recurrent public health threat. In biomedical studies with the zebrafish model, Project 3 has identified myelination in the developing brain as a target of domoic acid. They will use transgenic zebrafish and single-cell RNA-sequencing to identify the cell-specific mechanisms underlying effects of domoic acid, saxitoxin, and the cyanotoxin anatoxin-a in zebrafish embryos in vivo and will use human iPSC-derived 3D brain systems in vitro to elucidate toxin effects on neural and glial cell differentiation in human cells. Studies also will determine whether prior exposure to ubiquitous persistent organic pollutants may modify effects of subsequent exposure to saxitoxin and domoic acid. All projects will collaborate to link oceanic processes to human exposure, helping to define the exposure of susceptible human subpopulations. The Community Engagement Core will facilitate integration of the research with education and engagement of resource managers and other stakeholders. We also will improve awareness of emerging HAB issues for the public health community and develop new educational materials and interactive activities for K-12 classrooms, and for health care providers. An Administrative Core will encourage open discussion of planning, integration, and communication, and provide rigorous evaluation of progress in all aspects of the program.

NSF Award Abstract: See https://www.nsf.gov/awardsearch/show-award?AWD_ID=2418297

The data management plan for the program can be found here.