Effects Of Warming On Soil Bacterial Diversity And Recalcitrant Carbon Utilization Capacity In Tall

Under the background of the rapid development of modern industry,the impact of global climate change on all aspects is becoming more and more obvious.Especially global warming,under the conditions of overutilization of fossil fuels such as coal and oil,the proportion of greenhouse gases(such as CO2,CH4,N2O,etc.)in the atmosphere is much higher than before the industrial revolution.Greenhouse gases have the ability to absorb and re-radiate infrared rays,and the absorption of infrared radiation from the Earth’s surface causes a continuous increase in global surface temperatures.Soil organic matter is the largest carbon reservoir in terrestrial ecosystems,and small changes in organic matter can have a significant impact on atmospheric carbon dioxide concentrations and global climate change.As the main medium of organic matter formation and decomposition,soil microorganisms are the direct stewards of the global carbon balance.Therefore,predicting the response of microorganisms to global warming remains a very meaningful question.The experimental results of the previous stage of this project show that the content of soil organic carbon is significantly reduced by continuous warming through field experimental simulation,and this phenomenon occurs because of the large utilization of recalcitrant carbon by microorganisms.Therefore,the 16S rRNA gene amplicon sequencing technology was combined with traditional culture omics technology to further analyze the impact of long-term warming on soil microbial community changes,and lignin and cellulose were selected as the representatives of recalcitrant carbon to analyze the impact of warming on the ability of soil microorganisms to degrade recalcitrant carbon,so as to provide a reference for studying the structural and functional changes of microbial taxa under warming conditions,and also prepare for predicting future climate change.The main conclusions are as follows:1.The soil bacterial community structure of the warming treatment group and the control group was analyzed,and the results of 16S rRNA gene amplicon sequencing showed that the bacterial communities of all samples were dominated by Proteobacteria,Actinobacteriota,Firmicutes and Acidobacteriota,among which,The relative abundance of Proteobacteria phylum in A09C and A20C control groups was higher than that in A09W and A20 W warming treatment groups,the relative abundance of Actinobacteriota phylum in A09C and A20C control groups was lower than that in A09W and A20W warming treatment groups,and the relative abundance of Acidobacteriota phylum was relatively small in the control group and the warming treatment group,which indicated that the warming treatment caused differences in the diversity and richness of soil microorganisms.2.ATCC213-1(AT1),ATCC213-2(AT2),cellulose degradation(C)and lignin degradation(L)four media were selected for the isolation of cultureable taxa,and a total of 2831 strains of bacteria were isolated,and the diversity of cultureable taxa was measured by Shannon-Weiner index,Simpson index,Margalef richness index and Pielou uniformity index.The species diversity of AT1 and AT2 media was significantly higher than that of cellulose-degraded and lignin-degraded media,and the community diversity of the warming treatment group and the control group was analyzed,which showed that the warming treatment caused differences in the species diversity and community composition of soil microorganisms.3.Four media(aniline blue,guaiacol,manganese chloride,cellulose rescreening medium)were selected for lignin and cellulose degrading enzymes,and the isolated 2831 cultureable strains were verified by dye decolorization,and the results showed that compared with the A09W and A20W warming treatment groups,the proportion of lignin and cellulose degrading strains in the A09C and A20C control groups was higher.