Is bicarbonate directly used as substrate to participate in photosynthetic oxygen evolution

If the photosynthetic organisms assimilated only CO2 in the Archean atmosphere, hydroxide ion in the Archean seawater would not increase. If plants would not consume bicarbonate as a direct substrate during photosynthesis, it is difficult to explain the evolution of Earth's environment. To date, it is generally accepted that photosynthetic O-2 evolution of plants come from water photolysis. However, it should be debated by evaluating the effect of bicarbonate in photosynthetic O-2 evolution, analyzing the role of carbonic anhydrase (CA) in photosynthetic O-2 evolution, and the relationship between thylakoid CA and photosynthetic O-2 evolution. In the paper, I propose that bicarbonate is directly used as substrate to participate in photosynthetic O-2 evolution. The rationality of bicarbonate photolysis of plants is discussed from the thermodynamics and evolution of Earth's environment. The isotopic evidence that bicarbonate is not the direct substrate of photosynthetic O-2 release is reexamined, and the new explanation of bicarbonate photolysis in photosynthetic O-2 evolution is proposed.