Systems to monitor and forecast pelagic Sargassum inundation of coastal areas across the North Atlantic: present tools and future needs

Massive blooms of pelagic Sargassum, a brown macroalgae, have become a seasonally recurrent phenomenon in the Tropical Atlantic since 2011. These blooms have resulted in inundations along coastlines in western Africa and throughout the Intra-American Seas. The widespread nature of this phenomenon and complexities surrounding the growth and transport of these blooms in the open ocean have presented significant challenges to effectively monitoring and forecasting coastal inundations. Here we review 25 existing monitoring and forecasting systems, noting the unique aspects and common features among them and identifying the current gaps. Based on this review we present a conceptual model for the key elements necessary for operational monitoring and forecasting systems; recommending approaches that account for Sargassum distribution, amount, transport, and growth rates in predictions. We then provide specific recommendations for integrating improved monitoring and forecasting elements to the NOAA Atlantic Oceanographic and Meteorological Laboratory's Sargassum Inundation Risk and Ocean Viewer interactive maps.