Intensified land-use, sewage discharge, and climate change have likely favored disproportionate development of harmful algae in freshwaters. A new study found that blooms of one type of harmful algae, called cyanobacteria, have increased disproportionately over the past two centuries relative to other species, with the greatest increases since 1945.
Cyanobacteria pose a serious threat to drinking water sources worldwide because they can release toxins into the surrounding environment.
"While we already knew that cyanobacteria prefer warm and nutrient-rich conditions, ours is the first continental-scale study to show that the effect of nutrients, such as phosphorus and nitrogen, overwhelm those of global warming over the past 2 centuries," said Dr. Zofia Taranu, lead author of the Ecology Letters study. "Further work as a society will therefore be needed to reduce nutrient discharges to surface waters."