However, the rainfall also washed fertiliser into the surface water.
They took samples of 39 different waterbodies in and around towns and cities, predominantly in the province of Noord-Brabant.
They took two samples from each location every time.
In the laboratory they enriched one of the water samples with fertilisers and left the other sample as was, and then set both aside at normal or higher temperatures.
"Whether the water was 20 degrees or 25 degrees didn’t really make a difference," says research director Miquel Lurling.
"But at both temperatures the addition of nutrients caused an explosion in the cyanobacteria already present."
Pond with buffering capacity The research also showed that in water that initially contained less fertiliser, there was no explosion of cyanobacteria.
There are various techniques to make surface water more resistant to algal blooms, such as the maintenance and immobilising of fertilisers."
Many species of cyanobacteria produce toxins that can cause health problems if you come into contact with them or swallow them.
DOI: 10.3389/fmicb.2018.01851