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John Day MD's avatar

All interesting speculations of Gaia's past lives, Ugo. I hope it is good, organic coffee.

I wondered if you would mention C4 carbon-fixing plants.

"The evolution of “C4” plants has changed the game."

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The hatter's avatar

From the C4 article in wikipedia:

"The main carboxylating enzyme in C3 photosynthesis is called RuBisCO, which catalyses two distinct reactions using either CO2 (carboxylation) or oxygen (oxygenation) as a substrate. RuBisCO oxygenation gives rise to phosphoglycolate, which is toxic and requires the expenditure of energy to recycle through photorespiration. C4 photosynthesis reduces photorespiration by concentrating CO2 around RuBisCO."

C4 plants need less water, and thus can survive in warmer and drier regions. Ugo didn't say, but that's my guess.

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Ugo Bardi's avatar

Yep, but C4 plant didn't exist during the Mesozoic, so they played no role in the climate regulation. It was a completely different story during the Miocene, but a different story needs a different post!

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Alexander Chikunov's avatar

Very Insightful!!!

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