Improving forecasts for Karenia brevis in the Gulf of Mexico

Brevetoxins produced by Karenia brevis can be aerosolized and lead to severe respiratory irritation, with documented health risks for people with asthma. Economic impacts also occur as even healthy people avoid beach businesses when a “red tide” is reported to be in a region. However, the distribution of brevetoxin aerosol impact varies greatly, depending on patchiness of blooms and wind speed and direction. Locating and forecasting the blooms and respiratory risk are then necessary to reduce health and economic impacts. Previously, manual and qualitative evaluation determined the location and respiratory risk of these blooms at coarse resolutions (daily and county scale). The forecast has substantially been improved for nowcast timeliness with an automated capability that combines new resources and models. These include a chlorophyll-a fluorescence algorithm applied to Sentinel-3 satellite products, the HABscope (a microscope deployed by volunteers with digital video analysis), existing water sampling networks, improved weather forecasts, respiratory irritation risk models, and a bloom intensification forecast.