This summer’s heat brought warnings about harmful algal blooms across Britain and Ireland. In August, swimmers were warned not to enter a newly designated bathing site on the River Thames at Ham and Kingston after blue-green algae were detected. The swimming section of an Ironman event in Leeds was also cancelled because of a bloom in Waterloo Lake.
It is tempting to blame these events entirely on the heat. Cyanobacteria, one of the main culprits behind these blooms, certainly benefit from warm, sunny and relatively still conditions. But a heatwave does not create a harmful bloom from nothing.
