ORIGINALARTICLECombinedeffectofbicarbonateandwaterinphotosyntheticoxygenevolutionandcarbonneutralityYanyouWu1Received:21October2022/Revised:21October2022/Accepted:1November2022/Publishedonline:18November2022©TheAuthor(s),underexclusivelicencetoSciencePressandInstituteofGeochemistry,CASandSpringer-VerlagGmbHGermany,partofSpringerNature2022AbstractCarbonneutralityiswidelyconcernedandhighlyvaluedbymanycountries.Biospherehasalwaysmaintainedthebalancebetweenoxidizedorganicsub-stancesandassimilatedorganicmatter,resultinginnet-zerocarbondioxide(CO2)emissionsandmaintainingitsowncarbonneutrality.Naturehassetagoodexampleforhumanbeingstocoordinateoxygen(O2)balanceandCO2balance,andachievecarbonneutrality.Howdoesphoto-syntheticoxygenevolutioninitiatecarbonandwaterneu-trality?MysynthesisshowsthatphotosystemIIfunctionsascarbonicanhydrasetocatalyzethereactionofCO2hydrationunderphysiologicalconditions,andCO2hydra-tioncoupledwithchemicalequilibrium,H++HCO3-→1/2O2+2e-+2H++CO2,occursinaphotosystemIIcore-complex.Meanwhile,Ifocusedontherevisitingoffourclassicalheavyoxygen(O18)labelingexperimentsandfoundthatbicarbonatecanpromotephotosyntheticoxygenevolution,andthatphotosyntheticoxygenevolutioncanalternatelycomefrombicarbonateandwater,notonlywater.Bicarbonatephotolysisandwaterphotolysisaccountforhalfofthephotosyntheticoxygenevolutionrespec-tively,whichcanwellexplainthebicarbonateeffect,Doleeffectandplants’environmentaladaptability.Photosyn-theticoxygenevolutioninitiatedthejourneyofwatermetabolismandcarbonmetabolisminnature,whichledtothecouplingas1:1(mol/mol)stoichiometricrelationshipbetweenthereductionofCO2andoxidationoforganiccarbon,coordinatedtheevolutionoftheatmosphere,hydrosphere,lithosphereandbiosphere,andrealized‘‘carbonneutrality’’inthewholeEarthsystem.KeywordsBicarbonatephotolysis·Bicarbonateeffect·Carbonicanhydrase·Doleeffect·Waterphotolysis·Stoichiometricrelationship·Carbonmetabolism1IntroductionCarbonneutralityisawidelydiscussedtopicworldwide.Photosynthesis,which...
