A harmful algal bloom (HAB) is a biological process in which certain phytoplankton, cyanobacteria, or macroalgae proliferate rapidly and reach high biomass, producing adverse ecological or health effects via toxin production, hypoxia, or habitat alteration. HABs are driven by interactions among nutrient enrichment (especially nitrogen and phosphorus), light, temperature, hydrography, and species-specific physiology, often resulting in dominance of toxin-producing taxa such as some dinoflagellates, diatoms, or cyanobacteria. These blooms can disrupt food webs, cause mass mortalities of aquatic organisms, and generate bioaccumulated toxins that affect higher trophic levels, including humans, through consumption or exposure.
Just as the 2019–20 summer is remembered for devastating bushfires, the summer of 2024–25 is likely to be remembered for Australia-wide marine biological disruption associated with marine heat waves.
Ecology
Aug 12, 2025
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In March 2025, surfers and swimmers were the first to notice the harmful algal bloom taking hold in South Australian waters. People catching waves at a popular break on the Fleurieu Peninsula later reported feeling sick with ...
Ecology
Aug 11, 2025
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Scientists say they have at last solved the mystery of what killed more than 5 billion sea stars off the Pacific coast of North America in a decade-long epidemic.
Ecology
Aug 9, 2025
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For seaside communities reducing their pollution, nitrogen is a prime target. Often found in agricultural runoff and human waste, nitrogen and the nitrogen-containing nitrate molecule can enter coastal waters as a critical ...
Environment
Aug 4, 2025
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Microscopic algae in the ocean generate half the oxygen we breathe.
Ecology
Jul 29, 2025
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Researchers at the University of Birmingham have developed a powerful new method to detect harmful blue-green algae in freshwater lakes. Their method, which involves advanced mass spectrometry technology, can identify toxin-producing ...
Ecology
Jul 28, 2025
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The San Luis Reservoir in Merced County—one of California's largest artificial lakes—not only irrigates Central Valley farmland and supplies drinking water across the Silicon Valley and the South Bay, but also draws swimmers, ...
Environment
Jul 27, 2025
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Harmful algal blooms are not all the same. That's true even of the blooms within northwest Ohio, where researchers have long known that the strain of cyanobacteria that typically dominates blooms in the western basin of Lake ...
Ecology
Jul 24, 2025
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South Australia is desperate for help to tackle an unprecedented harmful algal bloom that has decimated marine life up and down the coast. While the extent of the damage is still unknown, my preliminary research suggests ...
Ecology
Jul 22, 2025
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An alga that threatens freshwater ecosystems and is toxic to vertebrates has a sneaky way of ensuring its success: It suppresses the growth of algal competitors by releasing chemicals that deprive them of a vital vitamin.
Ecology
Jul 16, 2025
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