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Super-Toxic Algae Blamed for Mass Deaths
8 Jul
Summary
- New study identifies algae as most toxic species found.
- Toxic bloom caused mass marine animal deaths in South Australia.
- Algae's neurotoxins have stronger effects than any other studied.
Marine researchers have identified the microalgae Karenia cristata as the most toxic species of its kind globally, following a catastrophic die-off of marine life in southern Australia last year. This discovery explains the immense environmental toll, including the deaths of hundreds of thousands of marine animals.
The algal bloom, which occurred in March 2025, produced neurotoxins that proved significantly more potent than those from any previously studied harmful algal bloom. Laboratory experiments revealed Karenia cristata's extreme toxicity even at low concentrations.
These findings have international implications, as similar cold-water Karenia species could bloom elsewhere. Previously, warm-water Karenia brevis in the southeastern US was considered the most devastating. The South Australian bloom, which began in March 2025, persisted for months, with residual effects still noted approximately 15 months later.
