Developing a Predictive Understanding of Harmful Cyanobacteria Growth, Toxins Production and Comparative Toxicity across Environmental Gradients

The extent to which climate change and stoichiometric interactions between N and P, particularly in combination with salinity, influence the growth, toxins production and toxicity of cyanobacteria harmful algal blooms (HAB) is poorly understood. Though ecological studies and monitoring activities have examined “toxicity,” these efforts are routinely limited by absence of toxins determination and comparative toxicity information related to water quality risks to public health and the environment. Because inconsistent approaches have been employed to quantify cyanotoxins, we present newly developed targeted and nontargeted analytical methods for quantitation of cyanotoxins in aquatic systems. We further identify a lack of robust aquatic toxicology data for cyanotoxins. Previous studies inconsistently analytically verify treatment levels, report purity of cyanotoxins employed for experiments and follow standardized methods. We are engaging these major research needs towards developing an advanced understanding of cyanoHAB risks to water quality, which we are beginning to address through mechanistic studies of proteomic, transcriptomic and behavioral pattern responses in the zebrafish and fathead minnow models for specific cyanotoxins and cyanobacteria. Further, commonly used water quality models lack inputs for toxins production, which inherently limits predictive capacity of HAB events. Some species of cyanobacteria have evolved unique adaptations to promote their growth under N-deficient conditions, but it remains poorly understood whether or not these traits actively exist simultaneously with toxins production. However, we identify N availability, relative to P and light, provides a dual regulatory mechanism that controls both biomass production and cellular synthesis of microcystin-LR. Developing predictive growth, toxins production and comparative toxicity models for cyanobacteria promises to improve forecasts, diagnoses and prevention of risks to the environment and human health.