In his new book, “The Devil’s Element: Phosphorus and a World out of Balance,” Dan Egan sounds alarms on both the scarcity and overabundance sides of the phosphorus-human equation. Thanks to heavy use of phosphorus in fertilizers, many experts foresee it becoming a scarce resource. But too much phosphorus in the wrong places — in the runoff to lakes, ponds and rivers — leads to toxic algae blooms that ravage bodies of water, kill tourism and make people sick. Read the full story by Milwaukee Journal Sentinel.