Siesta Key Beach. Photo by Dylan Campbell.

Red tide has plagued the Gulf of Mexico since the 1800s. Outbreaks of Karenia brevis, a harmful algae bloom, often worsened by runoff from pollution, has long been known to wreak havoc on marine ecosystems, killing off large swaths of fish, birds and other marine life. Red tide’s effect on humans—both here and across oceans—is the topic of Dr. Babara Kirkpatrick’s lecture, Florida & Australia: Red Tide “Cousins” and Their Impacts, November 6 at The Roskamp Institute.

A senior advisor at the Gulf of Mexico Coastal Ocean Observing System (GCOOS), Dr. Kirkpatrick has made a career in researching what harmful algae blooms can do to human health. A former respiratory therapist, Dr. Kirkpatrick began researching the effects of red tide on the respiratory system in 1996, during an extended red tide bloom that lasted for 30 months on Florida’s Gulf Coast.

“The group I worked with brought asthmatics to Siesta Key Beach, did a series of pre-testing, had them stay there for an hour during a red tide bloom, and found that there was a significant change in their pulmonary function after just that hour,” says Dr. Kirkpatrick. “It is an irritant to the upper airway as well as the lower airway. If you’re out on Siesta Key Beach on a busy Saturday there can be 10,000 people there. If you closed your eyes and listened to the beach during a bad bloom, it was just one continuous cough.”

Dr. Kirkpatrick’s expertise in the field came in handy in 2025, when an unprecedented red tide bloom—driven by Karenia cristata as opposed to Karenia brevis—hit Australia’s southern coastline. Dr. Kirkpatrick was contacted by Australia’s ABC Radio National to counteract claims from tourism agencies that red tide was harmless. “The nice message is that science is actually a lot more collaborative than I think people perceive it to be,” says Dr. Kirkpatrick.

Florida & Australia Red Tide “Cousins” and Their Impacts, Nov 6, 4pm, The Roskamp Institute, 2040 Whitfield Avenue, Sarasota.

Siesta Key Beach. Photo by Dylan Campbell.

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