File: Otavia_antiqua_3D_reconstruction.jpg (126.9 KB)

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>>5116467
This one supposedly evolved in the Tonian
I remember reading something about phosphate depletion being the main reason oxygen levels and evolutionary innovation were stagnant for so long even after the really early modern-like levels of the early great oxygenation (because dissolved oxygen in the ocean makes iron oxides which sequesters the phosphate which is then trapped under the seafloor forever) and a sustainable high oxygen level only became possible once enough land weathering with rivers and glacial flour and stuff happened to supply a large source of phosphate independent of the seafloor.
I don't know how true this is but if any anons here are experts in that sort of thing plz elucidate