New research finds that Earth had sufficient oxygen 1.4 billion years ago for animals to evolve. Therefore, low oxygen levels probably didn't hold back evolution, as scientists have long thought.
oxygen
Posted inResearch Spotlights
Past Phosphorus Runoff Causes Present Oxygen Depletion in Lakes
Sediment cores show how phosphorus pollution in the 1950s led to current, inherited hypoxia in lakes in the Alps.
Posted inResearch Spotlights
Manganese Deposits on Mars Suggest a Highly Oxidized Past
Data from the Curiosity rover suggest that the surface of Mars has experienced more strongly oxidizing conditions than previously thought.