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Cyanobacteria diversity challenges 'one-size-fits-all' algal bloom solutions

When populations of tiny aquatic organisms called cyanobacteria (formerly known as blue-green algae) explode, their toxic overgrowth can threaten human drinking water and cause wildlife deaths in events known as harmful algal blooms (HABs). In freshwater environments such as lakes, ponds and streams, a cyanobacterium known as Microcystis aeruginosa is responsible for most toxic harmful algal bloom episodes.

While most efforts on mitigating such events focus on reducing nutrients in the water, new research from University of California San Diego scientists reveals that there's more to the story, especially when considering future climate warming scenarios that could amplify such events.

School of Biological Sciences graduate student Mirte Kuijpers, Assistant Professor Sara Jackrel and their colleagues investigated Microcystis and found that different types of the cyanobacterium grow differently under various situations. They found that certain types have adapted to varied levels of nutrients, meaning a one-size-fits-all approach of nutrient reduction may not work best. Some types of Microcystis, they found, can survive in nutrient-poor waters and are better suited to survive warmer temperatures, which offers important new information as temperatures rise under climate change.

The research , "Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios," was published Feb. 5, 2025, in the journal Proceedings of the Royal Society B: Biological Sciences. The full authors list includes: Mirte Kuijpers, Catherine Quigley, Nicole Bray, Wenbo Ding, Jeffrey White and Sara Jackrel.