The lake has experienced algal blooms when excessive amounts of phosphorus and nitrogen are added to the water, --typically as runoff from fertilized agriculture, coupled with extreme precipitation followed by weak lake circulation and warm temperatures -- they said.
Unless agricultural practices are modified, the lake could face recurrences of extreme blooms, researchers from the Carnegie Institution in Washington said.
"The perfect storm of weather events and agricultural practices that occurred in 2011 is unfortunately consistent with ongoing trends, which means that more huge algal blooms can be expected in the future unless a scientifically guided management plan is implemented for the region," research leader Anna Michalak said in Carnegie release Monday.
The scientists combined sampling and satellite-based observations of the lake with computer simulations to study the 2011 bloom, finding that intensity at its peak was more than three times greater than for any other bloom on record.
Agricultural practices that increased nutrient runoff in the region during the last decade could lead to future mega-blooms, they said, unless steps are taken to reduce nutrients flowing into Lake Erie.
"Better management practices could be implemented to provide some relief to the problem," Michalak said.