Dolphins in Florida that became beached during cyanobacterial blooms showed signs of a version of Alzheimer’s that could be tied to neurotoxins found in the blooms.
That’s the conclusion of a new study in the peer-reviewed journal Communications Biology, published by Nature, from Florida scientists and a team from the Jackson-based nonprofit Brain Chemistry Labs. Similar blooms plague many Wyoming waters.
The researchers set out to test an unusual hypothesis, shared in a Brain Chemistry Labs press release: “Just as some adult humans with dementia are occasionally found wandering far from their homes, perhaps dolphins become similarly disoriented by suffering from a form of Alzheimer’s disease.”
The experiment involved studying the brains of 20 dolphins beached throughout the Indian River Lagoon in eastern Florida. The scientists found that dolphins that were stranded during the summer cyanobacterial bloom season had nearly 3,000 times the concentration of certain cyanobacterial toxins than those beached during non-bloom seasons.
The study shows a correlation, rather than a causation, between neurotoxins and brain changes reflecting Alzheimer’s in dolphins.
Paul Alan Cox is the executive director of Brain Chemistry Labs and an author on the study. He said the brain tissue of the dolphins resembled those of Alzheimer’s patients, with telltale markers in the topography of their brains.
“They have misfolded tau proteins. They have beta-amyloid plaques. So [for] all intents and purposes, [the dolphins] have Alzheimer's neuropathology,” he said.
Cyanobacterial blooms form in warm, slow-moving waters and are caused by high levels of nitrogen and phosphorus, often from agricultural runoff or sewage. In an ecosystem, neurotoxins found in the blooms can work their way up the food chain and bioaccumulate in apex predators, like dolphins.
Cox said the mammals studied in this research are a bit like canaries in a coal mine.
“ The dolphins, in this case, are functioning as a neurological sentinel and the fact that they're developing from these toxins a form of Alzheimer's disease makes us very concerned about human beings living in those same environments,” he said.
Cox pointed to bipartisan efforts to clean up waterways in Florida as “good news” in the effort to maintain more healthy coastal ecosystems in Florida.
Although the research was based on dolphins living on the other side of the country, cyanobacterial blooms are a problem around the world and the effects of climate change might cause them to become more severe and more pervasive, according to the U.S. Environmental Protection Agency.
“ This is a global phenomenon and we're not immune to that in Wyoming,” said Cox. “Fortunately, we know of no dolphins in Wyoming that have had Alzheimer's disease, but we do share concern about these cyanobacterial toxins.”
When it comes to his own backyard, Cox pointed to the fact that the town of Wilson doesn’t have a wastewater treatment plant.
“This is not a very sexy thing for a politician to announce for the campaign: ‘I'm going to produce better sewer treatment.’ But it's something we need to think about in Wyoming,” he said.
Cox added that Wyomingites should keep their distance from algal blooms in waterbodies around the state. This year, the Wyoming Department of Environmental Quality issued toxin advisories for 17 sites around the state and bloom advisories for 45 lakes and reservoirs.
“ If you see a blue green scum on a pond or lake, please don't go down there,” he said. “Please don't swim. Please don't drink it. Just stay away.”
To learn more about harmful cyanobacterial blooms and which lakes to avoid around the state, visit the Wyoming Department of Environmental Quality’s website.
