University of Miami scientists are studying a particularly insidious way in which toxic algal blooms may harm human health through the very air we breathe.

University of Miami scientists are studying a particularly insidious way in which toxic algal blooms may harm human health through the very air we breathe.
Volume 25 Number 1 | Spring 2019
by Robert C. Jones Jr.

Many South Floridians gripe with good reason about their stressful, time-consuming work commutes. But few can match the one made by Larry Brand, professor of marine biology and ecology in the Rosenstiel School of Marine and Atmospheric Science, multiple times last year. It wasn’t just the distance—a drive of two and a half hours or more from his South Miami home—but what awaited the phytoplankton ecologist when he arrived at his destination: foul hotspots of the toxic algae bloom outbreak that afflicted Florida for more than 10 months.

Beginning a typical day at the Caloosahatchee River, just outside the city of Fort Myers, Brand would submerge a one-liter bottle attached to a makeshift PVC pole to draw a sample of the turbid water. Capping the bottle, he would move on to several other affected bodies of water from Lake Okeechobee to Florida Bay, repeating the ritual at each site before heading home as the sun sank in the west.

Back in his Rosenstiel School lab on Virginia Key, Brand and his colleagues would culture and measure the water samples for levels of harmful algae. And then, for months on end, it was
rinse and repeat.

Throughout the year, the toxic algae Karenia brevis caused the worst red tide along Florida’s southwest coast in more than a decade, darkening Gulf of Mexico waters, killing marine life, and triggering respiratory distress and other ailments in locals and tourists. Karenia brevis can cause gastrointestinal and neurological disorders that develop within minutes, hours, or days after exposure.

Meanwhile, freshwater blue-green  cyanobacteria algae coated the Caloosahatchee and St. Lucie rivers and other freshwater canals. What that means for the residents’
long-term health remains unclear. But Brand is among a group of University of Miami scientists who are pooling their perspectives to find out.

The multidisciplinary team of biomedical researchers, ocean and atmospheric scientists, and engineers received Phase II funding for their Integrating Oceans and Human Health Sciences project via U-LINK (the University of Miami Laboratory for Integrative Knowledge) initiative.

“With the exception of brevetoxin (produced by the Florida red tide), little is known about the health effects of breathing aerosols with other algal toxins in them,” the team noted in its U-LINK proposal. “Our findings will be used to help devise strategies to lower risks.” 

Many, many Floridians live near canals”, Brand says, “and  a lot of the blue-green algae gets blown by the wind into these dead end waterways.


Despite their often disastrous effects on the environment, algae are, in one sense, “the good guys,” Brand notes. “If you didn’t have any algae at all in the ocean, you wouldn’t have any other life, because it’s the basis of the food chain.

“But sometimes the algae get out of control,” he explains. “Red tide toxins get into the air and into seafood. The effects are immediate, and that’s what most of   the research has concentrated on.

“We’re now looking at the long- term effects that the toxins in blue-green algae may have. The big question is, are they getting into the air?”

To answer that question, Cassandra Gaston, an assistant professor of atmospheric sciences, and Kimberly Popendorf, an assistant professor of ocean sciences, spent much of the past year, like Brand, roaming affected waterways throughout the region.

By testing air samples collected near the same rivers, lakes, and streams for toxins through a chemical extraction process, says Gaston, “we’re trying to find out whether some of the harmful algal blooms that we get in Florida other than red tide, specifically cyanobacteria, can become aerosolized.”

Another experiment will place blue-green algae water samples provided by Brand into the smaller of two wind-wave tanks at the Alfred C. Glassell Jr., SUSTAIN laboratory, subject the samples to different wind speeds, and measure the concentration of toxins that get transferred from water to air.

It will be the first such usage of the tank, according to Brian Haus, professor of ocean sciences and director of the SUSTAIN lab.


The SUSTAIN wind-wave tank is also serving as the test bed for Miller School of Medicine researcher Grace Zhai’s study on the health effects of exposure to harmful algal blooms. An associate professor of molecular and cellular pharmacology, Zhai works with fruit flies as models for neurological diseases. She is exposing fruit flies to aerosolized blue-green algae within the tank, then evaluating any resulting health effects. Zhai was an investigator on a study that identified a correlation between an algal toxin in the Western Pacific and a high incidence of a severe neurodegenerative disorder affecting males on the island of Guam. “Toxic algae is in our environment, and it’s getting concentrated,” she says. “No one has come close to showing toxicity from aerosolized particles, and no other animal model allows us to study this aspect of it.”

To measure anglers’ exposure levels to harmful algal blooms, Alberto J. Caban-Martinez, B.S. ’01, an assistant professor in the Miller School’s Department of Public Health Sciences, plans to use silicon-based wristbands like those that have been experimentally used to measure Florida firefighters’ exposure to hydrocarbons. Brand, who has spoken at standing-room-only meetings of county commissions, city councils, and environmental and citizens groups in Southwest Florida, says the health effects of harmful algal blooms clearly concern people the most. “We hope that our work will inform and inspire policymakers to come up with some way
of reducing the nutrient sources that are leading to these algal blooms,” Brand says.

image-toxic-stew-marine-life-480x320.pngThe unusually long red tide event that devastated Florida’s west coast for more than 10 months took a tragic toll on the state’s marine life. Hundreds of thousands of fish; hundreds of manatees, sea turtles, and dolphins; and even a 21-foot whale shark were among the casualties, many of them washing up dead on Florida beaches.

“Acute exposure likely causes a very painful death,” explains Jill Richardson, Ph.D. ’04, program director and senior lecturer in the Department of Marine Ecosystems and Society at the Rosenstiel School. “Chronic exposure to biotoxins is also believed to compromise the marine mammal immune system, making them more susceptible to other diseases”—which could, in turn, lead to the extinction or near-extinction of entire populations.

Marine mammals are considered “sentinels of the sea” that provide important clues about the health of our ocean ecosystems, including the public health impacts of harmful algal blooms. So when large numbers of marine mammals start dying, says Richardson, it’s a sign that ocean health is declining.

The situation “will only be exacerbated as our planet warms and coastal development continues,” she says. “We need to start productive conversations about what can be done to preserve these increasingly degraded coastal ecosystems—and to rethink how we utilize and interact with the ocean—before it’s too late.”