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HAB Research Focuses on Tidal Tributaries

February 6, 2024
Bloom Sample July 2023

Since 2018, the SCCF Marine Lab has sampled the Caloosahatchee and the C-43 canal to document and study harmful algal blooms (HABs). The research has found that identifying the source of water into the estuary is important.

“The challenge is that besides Lake Okeechobee, the potential sources, such as tidal creeks, have ‘nonpoint’ pollution and factors such as the season, rainfall, and mixing with the tides,” said Marine Lab Director Eric Milbrandt, Ph.D., “All of these aspects are important drivers of blooms.”

SCCF research has shown that certain conditions, including warm water greater than 86 degrees, a lower lake stage, and excess nitrogen, lead to cyanobacterial blooms.

“While blooms in Lake Okeechobee can be monitored from satellite imagery, those tools can’t be applied to the Caloosahatchee estuary because it is too narrow using today’s technology,” he said.

Bloom from July 2023 near the US 41 bridges in downtown Fort Myers.

SCCF research has now shifted to the tributaries of the tidal Caloosahatchee.

“The cyanobacterial bloom that occurred in July 2023 was not triggered by Lake O releases because there were no flows from the lake,” said Milbrandt. “Our hypothesis is that the tributaries may provide the conditions to initiate a bloom.”

The lab continues to use the River, Estuary and Coastal Network (RECON) to provide hourly temperature, salinity, dissolved oxygen, and chlorophyll (algae biomass) to monitor the system.

Through our existing partnerships with the Center for Coastal Solutions at the University of Florida (Phlips Lab) and a new partnership with Florida Department of Environmental Protection, the lab is now sampling the tributaries in the tidal portion of the Caloosahatchee along with the estuary itself.

“We are focused on Popash Creek, the Orange River, Hancock Creek, and Whiskey Creek,” said Milbrandt. “From this routine monthly sampling and sampling when a bloom occurs, we will understand which creeks can be targeted for further nutrient reductions.”


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