Was there molecular oxygen in the earth's primitive atmosphere?
aimeefarnum | Certified Educator
There was not molecular oxygen in early Earth's atmosphere. It was not until photosynthetic blue-green algae began to release oxygen by taking in carbon dioxide, sunlight, and water to create glucose and oxygen. Today the atmosphere is about 21% oxygen due to the delicate dance of photosynthesis/cellular respiration from producers and consumers. The original atmosphere was composed of hydrogen and helium until volcanic eruptions released carbon dioxide, Nitrogen, water vapor, sulfates, ammonia, and Methane.