增温下直接种间电子转移对泥炭地甲烷产生的作用OA

[Objective]To explore the role of direct interspecies electron transfer(DIET)mechanisms in methane production from the Zoige peatland on the Qinghai-Tibet Plateau under warming conditions,and to provide DIET-based methane mitigation strategies in peatlands under global warming.[Method]Soils growing three dominant plant species in the Zoige peatland on the Tibetan Plateau were sampled to construct methanogenic and electrochemical enrichments,which were amended with pectin or cellulose and incubated at 18℃.By adding biochar(as an electron transfer shuttle)and electrochemical experiments,the effects of DIET on methane production from plant organic complexes and its response to warming(28℃)were investigated.[Result]The addition of biochar into the soil enrichments elevated methane production from cellulose and pectin by 1.1 to 9.8-fold and increased maximum methanogenic rates by 1.4 to 12.3-fold,and the temperature sensitivity of methanogenesis was doubled following biochar addition.Chronoamperometry detected extracellular electrons generated by soil bacteria in the electrochemically enriched cultures,with a current density of 33.7 μA/cm2,and current consumption coupled methanogenesis by methanogenic archaea(21.2 μA/cm2)in electrochemical enrichments.16S rRNA gene diversity analysis revealed that biochar selectively enriched the electroactive bacterial family Geobacteraceae,along with methanogenic archaea communities including the families Methanosarcinaceae,Methanomethylophilaceae(electroactive uncharacterized),and the uncultured methanogen group Rice Cluster Ⅱ.Co-occurrence network analysis further indicated significantly positive correlations between Geobacteraceae or Cellulomonadaceae and Rice Cluster Ⅱ,suggesting that they implemented DIET-based conversion of the plant organic complexes to methane.[Conclusion]DIET plays a main role in methane production from plant organic complexes in Zoige peatland,particularly under the warming scenarios,thereby inhibiting interspecies electron transfer should be considered as one of the key strategies for methane mitigation in peatlands.