Research cruise investigating potential post-hurricane red tide
The Sanibel-Captiva Conservation Foundation reported that Marine Lab Director Dr. Eric Milbrandt is aboard a collaborative research cruise organized by the Florida Institute of Oceanography (FIO) that set sail on Oct. 18 from St. Petersburg to evaluate water quality conditions in the wake of Hurricane Ian.
“There has been a pattern over the last 20 years that long and intense red tide blooms can occur after the landfall of major hurricanes. It happened the year after Charley and Irma,” he said. “The oceanographic conditions preceding any bloom event give us clues to the sources of nutrients and the phytoplankton communities. We also will be looking for hypoxia and other unusual conditions.”
On the seven- to eight-day cruise, scientists and researchers will sample about 50 offshore sites from St. Petersburg to Naples to investigate the potential development of a red tide bloom due to Ian’s epic floodwaters. Red tide blooms typically occur in Florida in the fall, and hurricanes are suspected to play a role in stimulating blooms. The heavy rainfall and flooding cause land-based nutrients to flow outward to coastal waters and blooms feed off those nutrients.
The researchers, including scientists from Florida Gulf Coast University’s Water School, will be on call 24/7 on the FIO’s 78-foot R/V Hogarth, which has berths for 10 scientists and a wet and a dry lab. Aside from sampling, they will also retrieve some equipment displaced by the Category 4 hurricane by utilizing dive teams.
Sanibel & Captiva Islands Chamber of Commerce Board Chair Calli Johnson is on the cruise as one of FGCU’s dive safety officers.
“I am excited to document the changes caused by Hurricane Ian to our local waters. It’s important to me from a scientific perspective, as well as from a business standpoint,” she said. “When our waters are healthy that means positive changes for our tourism-based economy and for the fishermen on our waters daily.”
In organizing the cruise, FIO capitalized on its partnerships across the state, with members stepping up to provide data, logistical support, equipment and scientific supplies to the FGCU and SCCF.
“Like FIO’s response to the Piney Point discharge event, the deployment of resources to the areas impacted by Ian shows the importance of our state-supported mission. We are focused on bringing the best science capabilities of Florida’s universities and organizations to the forefront of these coastal ecosystems to better understand the storm’s overall impact,” FIO Director Dr. Monty Graham said.
Data collection will focus on water quality and the hurricane’s impact on coastal geology. Scientists at the FGCU and SCCF have long-term data to evaluate how local ecosystems and water quality were affected by the hurricane.
“We’ll use the data from the water samples to look for low dissolved oxygen and salinity levels indicating stratification of the water column to see if conditions are similar to 2018,” Marine Lab Manager A.J. Martignette said. “Freshwater sat on top of saltwater then and wasn’t mixing. We’ll see if the same situation is present.”
A rosette will be deployed from a control room on the research vessel to collect water samples at various depths.
The SCCF has been regularly testing 25 sites offshore from North Captiva to Sanibel since the 2018 red tide, thanks to funding support of the Vince family of Captiva through Goldman Sachs Gives. The sites are included in the cruise and will offer before and after data.
Some results of the research cruise will be immediate, such as dissolved oxygen and salinity levels. Other results including nutrient levels and phytoplankton will take up to a month.
“This is a tremendous opportunity to work with our colleagues at sea and advance the science of the West Florida shelf,” Milbrandt said. “We are grateful to all of the FIO members who donated equipment that our Marine Lab and FGCU lost in the hurricane to make the cruise possible.”