Oxygen and the biosphere

Oxygen is number three in the universe after hydrogen and helium. . With an atomic number of 8 that seems a little odd. Maybe the prevalence of oxygen relates to the extreme reactivity. And, of course, oxygen reacts especially with hydrogen, the main ingredient in the solar furnace. Rocks are made of oxygen. That, I would say, is not obvious. Cations, positive, are metals. The anions are negative and contain oxygen, especially silicate, sulfate, nitrate, carbonate and hydroxyl. Your body is 80% oxygen. This is much due to the 60% water, of which 89% is oxygen. But every category of biomolecules includes oxygen. " We live at the bottom of a poisonous atmosphere of oxygen" This makes sense and is even a bit profound, but 'poisonous' must be put on a chemical level, not biological. The video says that elemental oxygen, that is O2 gas, is non existent in the universe. I think that is a fair statement. The presence of pure oxygen could only occur in association with life. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx october 2023 addendum I just watched a Nova episode on early earth. The "oxygen explosion" also had profound implications on geology. In the absence of 02, metals would just hang around. The very early earth would have been full of toxic metals. The O2 released by the earliest blue green algae would have turned all metals into non-toxic silicates, carbonates, phosphates etc. This all started with the iron in the oceans. Oxygen stabilizes the chemistry of our home.