Warming Increases Amount of Harmful Algal Blooms

Communications Earth and Environment, 9 June 2025

This research suggests that warming coastal waters will significantly increase the occurrence of harmful algal blooms in high-latitude regions. The study projects that warmer ocean temperatures will lead to higher levels of these toxic blooms during spring and autumn, posing a heightened risk to seafood safety and wildlife. Some types of algae will flourish while others decrease, depending on how high summer temperatures rise and how much land runoff decreases coastal water salinity. Specifically, along the Norwegian coast, a projected 3°C warming could result in a 50% rise in diarrheic toxins but a 40% reduction in paralytic toxins, altering the specific risks to marine ecosystems and public health. Both human consumers and marine wildlife could become much more exposed to poisoning incidents if warming continues to push these delicate ecosystems into new algae conditions.

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