One of the most common bacterial threats to water quality is diarrheagenic E. coli, which thrives in warmer conditions. Beating the heat in the US is a little harder this summer than it used to be: E.
coli and cyanobacteria are causing widespread beach closures at lakes and rivers. It’s a problem exacerbated by climate change-fuelled warmer waters and more prolific downpours, which are creating perfect conditions for bacteria to flourish. Bacteria tend to grow in warm conditions, and between 1985 and 2009, lakes and ponds warmed at a rate of roughly 0.
3 deg C per decade. That shift is increasing the risk of blooms in historically cold places. The bacteria can cause a host of symptoms, including blisters, rashes, diarrhoea, muscle weakness and liver damage, to name a few.
Outbreaks can also tax ecosystems. All that comes at a price: In the US alone, preventing and treating harmful cyanobacterial blooms cost more than US$1 billion (S$1.3 billion) between 2010 and 2020, and the figure is likely to rise due to global warming.
Heavy rain often provides the “fuel and supplies” for bacterial spikes, according to Dr Kaitlin Reinl, a limnologist at the National Oceanic and Atmospheric Administration. Stormwater drives bacterial growth by washing phosphorus and nitrogen into lakes and rivers, where heatwaves can drive bacteria and algae growth. “Basically, temperature speeds up everything,” says Professor Hans-Peter Grossart, who teaches aquatic microbial ecology and biodiver.