Red Tide Grey Air

At the Mote Marine Laboratory in Sarasota, a row of glass cylinders hums with the sound of aerators, circulating seawater that has been tinted a faint, rusty orange. Inside, researchers are studying the cellular behavior of Karenia brevis, the dinoflagellate responsible for the catastrophic red tide outbreaks that plague Florida’s Gulf Coast. For years, the public health concern focused on the dead fish that wash ashore by the ton, clogging canals and ruining tourist seasons. Today, however, the focus has shifted to the air itself, as scientists seek to understand the long-term impact of breathing the aerosolized toxins carried inland by onshore winds.

When red tide blooms near the shore, the action of the surf breaks open the microscopic algae cells, releasing brevetoxins into the sea spray. This toxic mist can travel several miles inland, causing immediate respiratory irritation, coughing, and shortness of breath in healthy individuals, and severe distress for those with asthma or chronic lung disease. Recent studies suggest that chronic exposure to these airborne toxins may have cumulative effects on neurological health, prompting a sense of urgency among researchers who live in these affected communities. The state’s booming coastal population means that more people than ever are breathing this tainted air.

Along the beach near Lido Key, the air is clean today, but the memory of the last major bloom remains fresh. The restaurants along the water are busy, but thin yellow signs posted by the county warn visitors of the respiratory risks during active blooms. In the laboratory, scientists continue to analyze air filters collected from coastal monitoring stations, looking for trace amounts of the toxin that persist even when the water appears clear. It is a reminder that the boundary between the sea and the land is highly permeable, and that the health of the coast is inextricably linked to the air we breathe.