Project: WHCOHH - Physiological and behavioral plasticity in harmful algal bloom dynamics: variation across different habitats

The goal of this project is to identify commonalities and differences in regional bloom dynamics for two key harmful algal bloom (HAB) taxa, Alexandrium fundyense and Pseudo-nitzschia spp. The project’s central hypothesis is that HAB global biogeography and variable bloom and toxin dynamics are determined by a common repertoire of physiological and behavioral responses to environmental forcings and that the ability to understand, forecast, and mitigate HAB events requires a deep understanding of the plasticity of these repertoires within species and between populations. Novel, targeted, efficient, and data-rich in situ sampling paradigms developed with previous WHCOHH funding have revealed numerous unforeseen aspects of A. fundyense dynamics in the Nauset Marsh (NM), a long-studied inshore “model” bloom habitat. It is now clear that accurate rate estimates and behavioral patterns are needed for modeling and forecasting, and that these need to be generated as much as possible through in situ observation, a recognized strength of the WHCOHH.  In this project, the approach includes deployments of a portable, solar-powered observatory platform supporting remotely controlled instruments and profiling capabilities, the centerpiece being the IFCB, a unique autonomous underwater microscope for the in situ detection of rates of growth, accumulation, mortality, and life cycle stage conversions.  Variability in environmental forcing across years and among habitats provides a proxy for future climate scenarios, revealing the responses of these key HAB organisms under natural conditions. These novel observational and analytical approaches will be used to characterize the behaviors and responses of A. fundyense across a range of other habitats and environmental regimes.  They will also be directed towards Pseudo-nitzschia spp., a group that presents a growing public health threat to the northeast U.S. Improved understanding of critical physiological and behavioral features of both taxa are essential for accurate predictions of their climate responses and assessment of short- and long-term human health impacts.