Director of Environmental and Regulatory Affairs
Historically hurricanes and significant storm events wreak havoc on our water systems, causing immediate flooding and turbidity issues. But dangerous other problems may arise months later. Data and anecdotal reports predict an uptick in harmful algal blooms (HABs) in the warm seasons following these catastrophic events due to many factors, including excessive rainfall amounts, nutrient runoff, and the higher water capacity held in reservoirs and lakes.
In Florida, the abundance of rainfall from Hurricane Ian in 2022 flooded cities, countryside, golf courses, and agricultural lands. The flooding led to the release of excess nutrients usually bound to sediments. Nutrient runoff from agricultural fertilizers and herbicides, septic tanks, and plant and yard debris all ended up in the lakes, streams, rivers, and ultimately the Gulf of Mexico. The runoff of fertilizers and herbicides contains high amounts of nitrogen and phosphorus, which make it possible for HABs and Red Tide to be triggered, according to Hans Paerl, a marine and environmental scientist with The University of North Carolina at Chapel Hill. Furthermore, trees, leaves, and shrubs are washed into the waterways, depleting oxygen during decomposition. Oxygen depletion can lead to mortality in marine life, which happened similarly in the months and years after Hurricane Irma in 2017, killing nearly 600 sea turtles, 200 manatees, and over 200 dolphins.
Another severe phenomenon during large storm events arises from the upwelling and turnover within lake and pond systems. Upwelling and turnover describe when a bay or shallow lake recedes from one side to another ahead of a hurricane or large wind event, causing deep, colder, nutrient-rich water from well below to rise to the surface. Then, when the water returns to equilibrium within the bay or lake, the HABs feed from the newfound nutrients. The same concept occurs within lakes that experience flooding during large storms when the sediments are disturbed. Excess nutrients are released back into the water column, allowing algae and cyanobacteria to grow, contributing to the ongoing degradation of dams, lakes, rivers, and reservoirs, and exponentially increasing the pressure on wastewater treatment and water purification plants.
Knowing these environmental factors is essential to understanding the importance of taking precautionary steps to mitigate the onset of these algal and cyanobacteria blooms before they can get out of control. Protecting public health, livestock, and wildlife from toxin-producing cyanobacteria should be at the forefront of our actions as we move into the spring and summer months.
Get ahead of the curve to ensure you can deal with the upcoming storms and the subsequent HAB season!