Cyanobacteria bloom on the surface of hypertrophic waters in a pond in Seville, Spain. These blooms increase in frequency as temperatures and nutrient inputs increase, causing die-offs of birds and fish in Doñana National Park and other wetlands. Credit: Andy Green, EBD-CSIC.

Cyanobacteria bloom on the surface of hypertrophic waters in a pond in Seville, Spain. These blooms increase in frequency as temperatures and nutrient inputs increase, causing die-offs of birds and fish in Doñana National Park and other wetlands. Credit: Andy Green, EBD-CSIC.