Overview

• Published in Communications Biology, the analysis examined brains from 20 bottlenose dolphins stranded in Florida’s Indian River Lagoon between 2010 and 2019.
• Dolphins stranded during harmful algal bloom seasons carried up to 2,900 times more of the cyanobacterial neurotoxin 2,4‑DAB than those stranded outside bloom periods.
• Neuropathology included β‑amyloid plaques, hyperphosphorylated tau and TDP‑43 inclusions, alongside 536 altered genes linked to Alzheimer’s and disrupted GABAergic signaling with reduced GAD.
• Transcriptomic patterns correlated with bloom timing and 2,4‑DAB exposure, with hearing‑related gene signals noted, echoing prior reports of significant hearing loss in stranded dolphins.
• Researchers describe dolphins as environmental sentinels and caution that findings are correlative, as warming waters and nutrient runoff are increasing harmful bloom frequency and potential exposure risks for marine life and nearby communities.