A University of Alberta geomicrobiologist and his PhD student are part of a research team that has identified phosphorus as the mystery ingredient that pushed oxygen levels in the oceans high enough to establish the first animals on Earth 750 million years ago. By examining ancient-ocean sediments, Kurt Konhauser, student Stefan Lalonde and other colleagues discovered that as the last glacier to encircle Earth receded, leaving behind glacial debris containing phosphorus that washed into the oceans. Phosphorus is an essential nutrient that promoted the growth of cyanobacteria, or blue-green-algae, and its metabolic byproduct is oxygen. The new, higher oxygen levels...