"Cyanobacteria love warm water, therefore an increase in temperature during this century may stimulate their growth, especially that of the cytotoxic varieties, which could even produce more toxins and become more harmful," Rehab el-Shehawy, a researcher from the Madrid Institute for Advanced Studies in Water Technologies and co-author of the study published in the journal Water Research, said in a release.
The microorganisms are an environmental and health problem researchers said.
"These toxins may affect the liver and other organs [hepatotoxins], the nervous system [neurotoxins], different cells [cytotoxins], the eyes and mucous membranes, as well as causing dermatitis and allergies," Francisca F. del Campo, a researcher at the Autonomous University of Madrid, said in the release.
Del Campo said the researchers suspect cytotoxins may be behind some gastrointestinal disorders and other illnesses.
Studies carried out by the Center for Studies and Experimentation of Public Works found approximately 20 percent of Spanish reservoirs had cyanobacteria in concentrations higher than the guide level established by the World Health Organization for bathing water quality, researchers said.