Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and re...Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and response to warming.The mechanisms underlying warming-induced changes in C pools in black soils(Mollisols)remain unknown,owing to the stability of C pools and the complexity of their associated microbial communities.This study elucidates POC and MAOC contents and their microbial controls in black soils along a mean annual temperature(MAT)gradient from 0.6 to 7.3℃.The POC content(3.3-17 g kg^(−1))increased with MAT,while MAOC content(33-60 g kg^(−1))decreased,indicating accelerated C turnover with warming.Higher MAT shifted the bacterial communities from K-to r-strategies,aligning with increased POC content.The dominance of r-strategists facilitated rapid utilization and mineralization of organic compounds(e.g.,mainly with low C/N ratio),reducing MAOC and increasing POC through sustained plant residue inputs.This shift towards r-strategists also corresponded with increased abundance of saprotrophic fungi and stronger bacteria-saprotrophic fungi associations.Warming in colder regions may release available organic matter that saprotrophic fungi preferentially utilize over plant residues to minimize energy expenditure,decreasing POC decomposition.Our findings suggest that integrating microbial r-/K-strategies help to elucidate these mechanisms and simplify the interpretation of temperature effects on the dynamics of two main functional pools of soil organic matter.展开更多
We present mobile vehicle lidar observations in Tianjin, China during the spring, summer, and winter of 2016. Mobile observations were carried out along the city border road of Tianjin to obtain the vertical distribut...We present mobile vehicle lidar observations in Tianjin, China during the spring, summer, and winter of 2016. Mobile observations were carried out along the city border road of Tianjin to obtain the vertical distribution characteristics of PM2.5. Hygroscopic growth was not considered since relative humidity was less than 60% during the observation experiments. PM2.5 profile was obtained with the linear regression equation between the particle extinction coefficient and PM2.5 mass concentration. In spring, the vertical distribution of PM2.5 exhibited a hierarchical structure. In addition to a layer of particles that gathered near the ground, a portion of particles floated at 0.6–2.5-km height. In summer and winter, the fine particles basically gathered below 1 km near the ground. In spring and summer, the concentration of fine particles in the south was higher than that in the north because of the influence of south wind. In winter, the distribution of fine particles was opposite to that measured during spring and summer. High concentrations of PM2.5 were observed in the rural areas of North Tianjin with a maximum of 350 μg m^–3 on 13 December2016. It is shown that industrial and ship emissions in spring and summer and coal combustion in winter were the major sources of fine particles that polluted Tianjin. The results provide insights into the mechanisms of haze formation and the effects of meteorological conditions during haze–fog pollution episodes in the Tianjin area.展开更多
基金supported by the National Key Research and Development Program of China[Grant No.2022YFD1500202]Strategic Priority Research Program of the Chinese Academy of Sciences[Grant No.XDA28020202]+1 种基金China Postdoctoral Science Foundation[Grant No.2024M753332]the RUDN University Strategic Academic Leadership Program.
文摘Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and response to warming.The mechanisms underlying warming-induced changes in C pools in black soils(Mollisols)remain unknown,owing to the stability of C pools and the complexity of their associated microbial communities.This study elucidates POC and MAOC contents and their microbial controls in black soils along a mean annual temperature(MAT)gradient from 0.6 to 7.3℃.The POC content(3.3-17 g kg^(−1))increased with MAT,while MAOC content(33-60 g kg^(−1))decreased,indicating accelerated C turnover with warming.Higher MAT shifted the bacterial communities from K-to r-strategies,aligning with increased POC content.The dominance of r-strategists facilitated rapid utilization and mineralization of organic compounds(e.g.,mainly with low C/N ratio),reducing MAOC and increasing POC through sustained plant residue inputs.This shift towards r-strategists also corresponded with increased abundance of saprotrophic fungi and stronger bacteria-saprotrophic fungi associations.Warming in colder regions may release available organic matter that saprotrophic fungi preferentially utilize over plant residues to minimize energy expenditure,decreasing POC decomposition.Our findings suggest that integrating microbial r-/K-strategies help to elucidate these mechanisms and simplify the interpretation of temperature effects on the dynamics of two main functional pools of soil organic matter.
基金Supported by the National Key Project of Ministry of Science and Technology of China(2016YFC0203302)National 863 Program for High Technology Research and Development(2014AA06A512)+2 种基金National(Key)Basic Research and Development(973)Program of China(2014CB447900)National Natural Science Foundation of China(91544232,41305126,and 41605020)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB05040300)
文摘We present mobile vehicle lidar observations in Tianjin, China during the spring, summer, and winter of 2016. Mobile observations were carried out along the city border road of Tianjin to obtain the vertical distribution characteristics of PM2.5. Hygroscopic growth was not considered since relative humidity was less than 60% during the observation experiments. PM2.5 profile was obtained with the linear regression equation between the particle extinction coefficient and PM2.5 mass concentration. In spring, the vertical distribution of PM2.5 exhibited a hierarchical structure. In addition to a layer of particles that gathered near the ground, a portion of particles floated at 0.6–2.5-km height. In summer and winter, the fine particles basically gathered below 1 km near the ground. In spring and summer, the concentration of fine particles in the south was higher than that in the north because of the influence of south wind. In winter, the distribution of fine particles was opposite to that measured during spring and summer. High concentrations of PM2.5 were observed in the rural areas of North Tianjin with a maximum of 350 μg m^–3 on 13 December2016. It is shown that industrial and ship emissions in spring and summer and coal combustion in winter were the major sources of fine particles that polluted Tianjin. The results provide insights into the mechanisms of haze formation and the effects of meteorological conditions during haze–fog pollution episodes in the Tianjin area.
