摘要
【目的】阐明土壤有机碳(soil organic carbon,SOC)年龄和微生物多样性的空间分布特征,并探讨微生物多样性、网络复杂度与SOC年龄之间的关系。同时,定量评估微生物多样性、网络复杂度、气候、植被和土壤性质对SOC年龄的相对贡献。【方法】利用全球土壤放射性碳(Δ^(14)C)实测数据和环境变量数据,构建了9种SOC年龄的机器学习预测模型,并筛选出最优的SOC年龄预测模型。基于全球土壤微生物16S rRNA基因数据和环境变量数据,通过微生物网络分析、多元回归分析、随机森林模型和结构方程模型,分析了SOC年龄与土壤微生物之间的相关性,并揭示SOC年龄的主要驱动因素。【结果】土壤微生物丰富度随着绝对纬度的增加而显著降低(P<0.001),在赤道附近丰富度指数较高,而在高纬度地区整体呈现较低的丰富度指数。所构建的9种机器学习模型中,基于规则回归模型的预测效果最好(R^(2)=0.77,RMSE=0.84)。土壤微生物丰富度指数和香农指数与绝对纬度和SOC年龄均为显著负相关(P<0.001)。将全球土壤划分为少年组(44-171年)、中年组(172-321年)和老年组(322-5035年)后,其网络密度分别为少年土壤组(0.400)>中年土壤组(0.285)>老年土壤组(0.125)。多元回归分析、随机森林模型和结构方程模型均表明微生物网络复杂度对SOC年龄的解释度最大(34%),远超过了植被(10%)和气候(6%)因素。【结论】全球土壤SOC年龄与土壤微生物多样性及网络复杂度显著负相关,SOC年龄越大,微生物多样性越低,微生物网络结构越简单。微生物网络的复杂度是影响SOC年龄的关键因素,其影响显著超过了植被和气候等传统因素。这些结果为理解SOC年龄的驱动机制提供了新的视角,建议在未来模拟SOC动态过程时应充分考虑微生物网络的作用。
[Objective]To clarify the spatial distribution characteristics of soil organic carbon(SOC)age and microbial diversity,explore the relationship of microbial diversity and network complexity with SOC age,and quantitatively assess the relative contributions of microbial diversity,network complexity,climate,vegetation,and soil properties to SOC age.[Methods]Using global soil radiocarbon(Δ^(14)C)data and environmental variable data,we constructed nine machine learning models for predicting SOC age and selected the best-performing model.Based on global soil microbial 16S rRNA gene data and environmental variable data,microbial network analysis,multiple regression analysis,random forest models,and structural equation modeling were employed to analyze the correlation between SOC age and soil microorganisms and identify the main driving factors of SOC age.[Results]Soil microbial richness decreased with the rise in absolute latitude(P<0.001),being higher near the equator and lower at higher latitudes.Among the nine machine learning models constructed,the rule regression model showed the best prediction performance(R^(2)=0.77,RMSE=0.84).Soil microbial richness and Shannon index were negatively correlated with absolute latitude and SOC age(P<0.001).The global soils were classified into young(44-171 a),middle-aged(172-321 a),and old(322-5035 a)soil groups,and the network densities followed a trend of young soil group(0.400)>middle-aged soil group(0.285)>old soil group(0.125).Multiple regression analysis,random forest models,and structural equation modeling all showed that microbial network complexity explained the largest portion of SOC age variation(34%),far surpassing vegetation(10%)and climate(6%).[Conclusion]Global soil SOC age has significantly negative correlations with soil microbial diversity and network complexity.The soil with old SOC has lower microbial diversity and simpler microbial network structure.Microbial network complexity is a key factor influencing SOC age,and its impact is significantly greater than that of vegetation and climate.These results provide new insights into the driving mechanisms of SOC age and suggest that future models of SOC dynamics should fully consider the role of microbial interaction network.
作者
李殿甲
韩冰
李晓洁
马晶晶
张佳宝
贾仲君
LI Dianjia;HAN Bing;LI Xiaojie;MA Jingjing;ZHANG Jiabao;JIA Zhongjun(State Key Laboratory of Black Soils Conservation and Utilization,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun,Jilin,China;University of Chinese Academy of Sciences,Beijing,China;State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing,Jiangsu,China)
出处
《微生物学报》
北大核心
2025年第8期3254-3272,共19页
Acta Microbiologica Sinica
基金
黑土地保护与利用全国重点实验室青年创新项目(2023HTDGZ-QN-01)
中国科学院战略性先导科技专项(XDA28020203)。
