Dolphins poisoned by algae also showed signs of Alzheimer’s-like brain disease

Toxins produced by blue green algae that have increasingly polluted Florida waters have been found in dead dolphins that also showed signs of Alzheimer’s-like brain disease, according to a new study led by University of Miami researchers.

The study, published Wednesday in the peer-reviewed journal PLOS One, is the first to show detectable levels of the toxin, commonly called BMAA, in dolphin brains that also displayed degenerative damage similar to Alzheimer’s, Lou Gehrig’s disease and Parkinson’s in humans. While more work needs to be done to determine whether the toxins cause the disease, the study concludes dolphins and their complex brains could provide a key sentinel for the potential threat from toxic algae blooms to humans.

“Not to be too political, but it goes to show the health of marine animals and water quality,” said David Davis, lead author and a University of Miami Miller School of Medicine neuropathologist. “Everything’s directly related.”

The findings add to a growing body of research that focuses on the health threat from harmful algae blooms, which climate scientists warn could worsen as the planet warms. South Florida is particularly vulnerable with miles of coast, a lake that is a third of the size of Rhode Island, rivers and estuaries and an agricultural industry and swelling population that continue to feed blooms with pollution from fertilizer and sewage.

This past year, nearly 150 dead dolphins turned up in Florida waters after a widespread red tide along the Gulf Coast coincided with freshwater blue-green algae washing down the Caloosahatchee River. The carnage prompted the state’s new governor to order a task force assembled to tackle damaging blue-green algae blooms just after he took office.

The task force is expected to be created after a chief science officer, another position Gov. Ron DeSantis created, is selected, Department of Environmental Protection spokeswoman Dee Ann Miller said in an email. The science officer should be named in the next few weeks, she said.

Two years ago, UM researchers confirmed high levels of toxin from algae in sharks, concluding the ocean’s big, long-living predators accumulate the toxin in their brains over time, and warned against eating shark.

The connection between the toxin and brain disease is still relatively new and not without controversy. Scientists first discovered the link after a botanist visiting Guam to research cancer took another look at a decades-old mystery surrounding a degenerative brain disease, Discover Magazine reported in 2011. The disease hit nearly every household in a small village, leading researchers to focus on the seed from cycads, a plant often confused with palms and a staple of villagers’ diet.

The seeds contain BMAA, but researchers concluded villagers could never consume enough to make them sick. The botanist, Paul Cox, found the connection when he discovered the villagers also ate fruit bats, which feasted on the seeds and had a much higher concentration of BMAA because it accumulated in their bodies over time, according to a 2012 Environmental Health Perspectives account.