Award: OCE-2309081

In recent years southern Florida has been impacted by multiple severe hurricanes, including Hurricanes Ian, Helene and Milton, which have delivered unprecedented amounts of land derived nutrients and organic matter to coastal waters.  These storms have also presented a unique opportunity for this project to examine and model the impact of these inputs on coastal nutrient cycling, blooms of the Florida Red Tide and coastal dead zones.  Project outcomes include important knowledge of the relationships between coastal land based nutrient inputs derived from increasing coastal eutrophication related to increasing population densities and blooms of the annually recurring toxic dinoflagellate Karenia brevis.  Changes in bloom initiation and 4 to 5 month increases in bloom duration relate to increasing temperatures due to climate forcing, with changes in the flow of the Caloosahatchee River predicting bloom severity.  A model of Hurricane Ian impacts on K. brevis confirmed these results, demonstrating earlier bloom initiation and higher bloom biomass with hurricane nutrient and organic inputs to coastal waters than without these inputs.  Project outcomes also include increased knowledge of respiration rates within hurricane impacted waters and red tides and the potential relationship between increased respiration and coastal dead zones, knowledge which has resulted from a new, faster, cheaper method for measurement of light dependent respiration rates developed and tested during the project.  This knowledge is useful for potential future management of Florida Red Tide.

Last Modified: 03/31/2026
Modified by: Cynthia A Heil