Pollution and toxic algae strand dolphins in Florida. They are a serious warning coming from the sea.
Common dolphins found stranded in Florida showed neurological signs similar to those of Alzheimerand that’s not good for us humans either.
The surprising research finding, the results of which were published in Communications Biology, shows that the serious effect is most likely due to exposure to toxins released by harmful algae.
Between 2010 and 2019, researchers analyzed the brains of 20 dolphins stranded in the Indian River Lagoon, a coastal area increasingly affected by agricultural discharges and sewage that favor the proliferation of cyanobacteria. All animals showed significant traces of 2,4-diaminobutyric acid (2,4-DAB), a potent neurotoxin produced by these microalgae.
Specimens found during algal bloom seasons — from June to November — had up to 2,900 times more concentration of the toxin than those collected in non-blooming months.
According to the investigator David A. Davisfrom the Miller School of Medicine at the University of Miami, this exposure “is certainly not beneficial” and may contribute to neurodegenerative processes similar to those of Alzheimer’s, cites . Although the study does not prove a direct causal relationship, the results suggest an unsettling link between marine pollution and cognitive degeneration.
Analysis revealed deposits of abnormal proteins — beta-amyloid, tau and TDP-43 — all associated with memory loss and neuron destruction in humans with dementia. Also identified were profound genetic changes: 536 genes showed abnormal behavior, including APOE, the main genetic risk factor for Alzheimer’s, which was up to six times more active than normal.
The Indian River Lagoon, measuring more than 250 kilometers, is suffering from eutrophication and global warming, which prolong and intensify toxic algal blooms. The phenomenon is not exclusive to Florida: similar cases have been recorded in fish, turtles and even in human populations exposed to contaminated seafood.
Dolphins, due to their longevity, diet and human-like brain structure, are considered ideal ecological sentinels. The correlation between strandings and times of greatest algal activity, as well as the mutations observed in genes related to hearing and orientation, suggest that these toxins could compromise not only the cognitive functions, but also the communicative capabilities of these mammals.
Scientists warn that 2,4-DAB is just one piece of a larger puzzle. Other algal toxins also cause memory loss and neuronal death.
For beachgoers, a stranded dolphin is a tragedy that ends with the dolphin; for science, it is a warning signal coming from the sea, directed at us.
