The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits...The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits and their allometric relationships in an 8-year-old Calocedrus macrolepis plantation in southwest China across three slope positions(upslope,mesoslope and downslope).The measured growth traits included tree height(H),diameter at breast height(D),crown size(Crown),wood volume(V)and height under branch(HUB).The study also explored spatial variations in soil properties and microbial communities.Results showed that slope position altered allometric growth pattern,with larger allometric exponents at downslope for H,D and V relative to Crown and HUB,suggesting improved wood growth.Soil nutrient levels(nitrogen,phosphorus and available potassium)and microbial diversity,particularly the relative abundance of bacterial phyla such as Actinobacteria and Chloroflexi,were greater at mesoslope and downslope.Our study identified phosphorus and potassium as key drivers of enhanced allometric relationships.Functional groups such as Endomycorrhizal and Ectomycorrhizal fungi,and functional groups involved in nitrogen cycling(Nitrogen respiration,Nitrate respiration),were strongly correlated with allometric exponents for D,V and Crown relative to HUB,suggesting their role in supporting structural growth and canopy expansion.These findings emphasize that variations in soil nutrients and microbial communities across slope positions regulate tree growth and allometry,with bacterial communities exerting a stronger influence than fungi.These insights contribute to sustainable forest management,particularly in optimizing planting site selection for improved tree growth in mountainous regions.展开更多
The biosphere interacts and co-evolves with natural environments.Much is known about the biosphere’s response to ancient environmental perturbations,but less about the biosphere’s influences on environmental change ...The biosphere interacts and co-evolves with natural environments.Much is known about the biosphere’s response to ancient environmental perturbations,but less about the biosphere’s influences on environmental change through earth history.Here,we discuss the roles of microbes in environmental changes during the critical Permian-Triassic(P-Tr)transition and present a perspective on future geomicrobiological investigations.Lipid biomarkers,stable isotopic compositions of carbon,nitrogen and sulfur,and mineralogical investigations have shown that a series of microbial functional groups might have flourished during the P-Tr transition,including those capable of sulfate reduction,anaerobic H2S oxidation,methanogenesis,aerobic CH4oxidation,denitrification,and nitrogen fixation.These microbes may have served to both enhance and degrade the habitability of the Earth-surface environment during this crisis.The integrated microbial roles have enabled the Earth’s exosphere to be a self-regulating system.展开更多
Microbes not only show sensitive responses to environmental changes but also play important roles in geochemical and geophysical systems. It is well known that microbes have caused major changes in surface environment...Microbes not only show sensitive responses to environmental changes but also play important roles in geochemical and geophysical systems. It is well known that microbes have caused major changes in surface environments and biogeochemical cycles through Earth history. Microbial processes can also induce the synthesis of certain minerals under Earth-surface conditions that previously were believed to form only under high temperatures and pressures in the deep Earth. For example, microbes can promote the conversion of smectite to illite, synthesis of authigenic plagioclase, precipitation of dolomite, and biotransformation of geolipids. These effects of microbes are due to their large surface/volume ratios, enzyme production, and abundant functional groups. Microbial catalyzation of chemical reactions proceeds through reaction-specific enzymes, a decrease in Gibbs' s free energy, and/or break through the dynamics reaction thresholds via their metabolisms and physiology. Microbes can lower the surface free energy of mineral nuclei via biophysical adsorption due to their large surface/volume ratios and abundant functional groups. The mineral precipitation and transformation processes induced by microbes are functionally equivalent to geological processes operating at high temperatures and pressures in the deep Earth, suggesting that microbial processes can serve as analogs to deep abiotic processes that are difficult to observe.展开更多
Background Macrophytes may modify benthic biodiversity and biogeochemistry via radial oxygen loss from roots.This condition contrasts sediments anoxia,allows roots respiration,and facilitates aerobic microbial communi...Background Macrophytes may modify benthic biodiversity and biogeochemistry via radial oxygen loss from roots.This condition contrasts sediments anoxia,allows roots respiration,and facilitates aerobic microbial communities and processes in the rhizosphere.Simultaneously,the rhizosphere can stimulate anaerobic microorganisms and processes via exudates or by favoring the build-up of electron acceptors as nitrate.As eutrophication often results in organic enrichment in sediments and large internal nutrients recycling,an interesting research question is to investigate whether plants maintain the capacity to stimulate aerobic or anaerobic microbial communities and processes also under elevated organic pollution.Methods A manipulative experiment was carried out under laboratory-controlled conditions.Microcosms containing bare sediments and sediments transplanted with the macrophyte Vallisneria spiralis L.were created.The effect of the plant was investigated on sediments with moderate(8%)and elevated(21%)organic matter content,after an acclimatization period of 30 days.Chemical and physical parameters,microbial community composition and the potential rates of nitrification,denitrification and nitrate ammonification were measured at two different depths(0–1 and 1–5 cm)after the acclimatization period to evaluate the role of roots.Results Vallisneria spiralis grew and assimilated pore water nutrients at the two organic matter levels and vegetated sediments had always nutrient-depleted porewaters as compared to bare sediments.Nitrifying microbes had a lower relative abundance and diversity compared to denitrifying bacteria.However,regardless of the organic content,in vegetated sediments nitrifiers were detected in deeper horizons as compared to bare sediments,where nitrification was confined near the surface.In contrast,potential denitrification rates were not affected by the presence of roots,but probably regulated by the presence of nitrate and by root-dependent nitrification.Potential nitrate ammonification rates were always much lower(<3%)than potential denitrification rates.Conclusions Vallisneria spiralis affects N-related microbial diversity and biogeochemistry at moderate and elevated organic matter content,smoothing bottom water–pore water chemical gradients and stimulating nitrification and nitrogen loss via denitrification.These results suggest the possibility to deploy V.spiralis as a nature-based solution to counteract eutrophication in freshwater systems impacted by high loads of organic matter,for example,downstream of wastewater treatment plants.展开更多
Geobiology is a new discipline on the crossing interface between earth science and life science, and aims to understand the in- teraction and co-evolution between organisms and environments. On the basis of the latest...Geobiology is a new discipline on the crossing interface between earth science and life science, and aims to understand the in- teraction and co-evolution between organisms and environments. On the basis of the latest international achievements, the new data presented in the Beijing geobiology forum sponsored by Chinese Academy of Sciences in 2013, and the papers in this special issue, here we present an overview of the progress and perspectives on three important frontiers, including geobiology of the critical periods in Earth history, geomicrobes and their responses and feedbacks to global environmental changes, and geobiology in extreme environments. Knowledge is greatly improved about the close relationship of some significant biotic events such as origin, radiation, extinction, and recovery of organisms with the deep Earth processes and the resultant envi- ronmental processes among oceans, land, and atmosphere in the critical periods, although the specific dynamics of the co-evolution between ancient life and paleoenvironments is still largely unknown. A variety of geomicrobial functional groups were found to respond sensitively to paleoenvironmental changes, which enable the establishment of proxies for paleoenvi- ronmental reconstruction, and to play active roles on the Earth environmental changes via elemental biogeochemical cycles and mineral bio-transforrnations, but to be deciphered are the mechanisms of these functional groups that change paleoenvi- ronmental conditions. Microbes of potential geobiology significance were found and isolated from some extreme environments with their biological properties partly understood, but little is known about their geobiological functions to change Earth envi- ronments. The biotic processes to alter or modify the environments are thus proposed to be the very issue geobiology aims to decipher in the future. Geobiology will greatly extend the temporal and spatial scope of biotic research on Earth and beyond. It has great potential of application in the domains of resource exploration and global change. To achieve these aims needs coor- dinative multidisciplinary studies concerning geomicrobiology and related themes, database and modeling of biogeochemical cycles, typical geological environments, and coupling of biological, physical, and chemical processes.展开更多
基金supported by the Essential Scientific Research of Chinese National Nonprofit Institute(CAFYBB2021ZW003)National Natural Science Foundation of China(32022058)+1 种基金the Candidates of the Young and Middle-Aged Academic Leaders of Yunnan Province of China(202205AC160041)Yunnan Fundamental Research Projects(202201AT070258 and 202301AV070002)and Xingdian Talent Support Program(XDYC-QNRC-2022-0231).
文摘The allometric relationships between growth traits are critical to trees’fitness,yet the mechanisms by which slope position affects tree growth and allometry remain poorly understood.This study examined growth traits and their allometric relationships in an 8-year-old Calocedrus macrolepis plantation in southwest China across three slope positions(upslope,mesoslope and downslope).The measured growth traits included tree height(H),diameter at breast height(D),crown size(Crown),wood volume(V)and height under branch(HUB).The study also explored spatial variations in soil properties and microbial communities.Results showed that slope position altered allometric growth pattern,with larger allometric exponents at downslope for H,D and V relative to Crown and HUB,suggesting improved wood growth.Soil nutrient levels(nitrogen,phosphorus and available potassium)and microbial diversity,particularly the relative abundance of bacterial phyla such as Actinobacteria and Chloroflexi,were greater at mesoslope and downslope.Our study identified phosphorus and potassium as key drivers of enhanced allometric relationships.Functional groups such as Endomycorrhizal and Ectomycorrhizal fungi,and functional groups involved in nitrogen cycling(Nitrogen respiration,Nitrate respiration),were strongly correlated with allometric exponents for D,V and Crown relative to HUB,suggesting their role in supporting structural growth and canopy expansion.These findings emphasize that variations in soil nutrients and microbial communities across slope positions regulate tree growth and allometry,with bacterial communities exerting a stronger influence than fungi.These insights contribute to sustainable forest management,particularly in optimizing planting site selection for improved tree growth in mountainous regions.
基金supported by Notional Basic Research Program of China (Grant No. 2011CB808800)National Natural Science Foundation of China (Grant No. 41202240)+2 种基金State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Grant No. GBL11202, GBL11302 )the "111" Project (Grant No. B08030)the Fundamental Research Funds for the Central Universities, China University of Geosciences (Grant No. CUG120117)
文摘The biosphere interacts and co-evolves with natural environments.Much is known about the biosphere’s response to ancient environmental perturbations,but less about the biosphere’s influences on environmental change through earth history.Here,we discuss the roles of microbes in environmental changes during the critical Permian-Triassic(P-Tr)transition and present a perspective on future geomicrobiological investigations.Lipid biomarkers,stable isotopic compositions of carbon,nitrogen and sulfur,and mineralogical investigations have shown that a series of microbial functional groups might have flourished during the P-Tr transition,including those capable of sulfate reduction,anaerobic H2S oxidation,methanogenesis,aerobic CH4oxidation,denitrification,and nitrogen fixation.These microbes may have served to both enhance and degrade the habitability of the Earth-surface environment during this crisis.The integrated microbial roles have enabled the Earth’s exosphere to be a self-regulating system.
基金supported by National Natural Science Foundation of China (Grant No. 41330103)the "111 Project" (Grant No. B08030)
文摘Microbes not only show sensitive responses to environmental changes but also play important roles in geochemical and geophysical systems. It is well known that microbes have caused major changes in surface environments and biogeochemical cycles through Earth history. Microbial processes can also induce the synthesis of certain minerals under Earth-surface conditions that previously were believed to form only under high temperatures and pressures in the deep Earth. For example, microbes can promote the conversion of smectite to illite, synthesis of authigenic plagioclase, precipitation of dolomite, and biotransformation of geolipids. These effects of microbes are due to their large surface/volume ratios, enzyme production, and abundant functional groups. Microbial catalyzation of chemical reactions proceeds through reaction-specific enzymes, a decrease in Gibbs' s free energy, and/or break through the dynamics reaction thresholds via their metabolisms and physiology. Microbes can lower the surface free energy of mineral nuclei via biophysical adsorption due to their large surface/volume ratios and abundant functional groups. The mineral precipitation and transformation processes induced by microbes are functionally equivalent to geological processes operating at high temperatures and pressures in the deep Earth, suggesting that microbial processes can serve as analogs to deep abiotic processes that are difficult to observe.
基金financially been supported by the Program“FIL-Quota Incentivante”of University of Parmaco-sponsored by Fondazione Cariparma
文摘Background Macrophytes may modify benthic biodiversity and biogeochemistry via radial oxygen loss from roots.This condition contrasts sediments anoxia,allows roots respiration,and facilitates aerobic microbial communities and processes in the rhizosphere.Simultaneously,the rhizosphere can stimulate anaerobic microorganisms and processes via exudates or by favoring the build-up of electron acceptors as nitrate.As eutrophication often results in organic enrichment in sediments and large internal nutrients recycling,an interesting research question is to investigate whether plants maintain the capacity to stimulate aerobic or anaerobic microbial communities and processes also under elevated organic pollution.Methods A manipulative experiment was carried out under laboratory-controlled conditions.Microcosms containing bare sediments and sediments transplanted with the macrophyte Vallisneria spiralis L.were created.The effect of the plant was investigated on sediments with moderate(8%)and elevated(21%)organic matter content,after an acclimatization period of 30 days.Chemical and physical parameters,microbial community composition and the potential rates of nitrification,denitrification and nitrate ammonification were measured at two different depths(0–1 and 1–5 cm)after the acclimatization period to evaluate the role of roots.Results Vallisneria spiralis grew and assimilated pore water nutrients at the two organic matter levels and vegetated sediments had always nutrient-depleted porewaters as compared to bare sediments.Nitrifying microbes had a lower relative abundance and diversity compared to denitrifying bacteria.However,regardless of the organic content,in vegetated sediments nitrifiers were detected in deeper horizons as compared to bare sediments,where nitrification was confined near the surface.In contrast,potential denitrification rates were not affected by the presence of roots,but probably regulated by the presence of nitrate and by root-dependent nitrification.Potential nitrate ammonification rates were always much lower(<3%)than potential denitrification rates.Conclusions Vallisneria spiralis affects N-related microbial diversity and biogeochemistry at moderate and elevated organic matter content,smoothing bottom water–pore water chemical gradients and stimulating nitrification and nitrogen loss via denitrification.These results suggest the possibility to deploy V.spiralis as a nature-based solution to counteract eutrophication in freshwater systems impacted by high loads of organic matter,for example,downstream of wastewater treatment plants.
基金supported by the project on Strategy Development of Geobiology and Astrobiology from Chinese Academy of Sciences, National Basic Research Program of China (Grant No. 2011CB808800)National Natural Science Foundation of China (Grant No. 41330103)the "111" Program from Ministry of Education of China (Grant No. B08030)
文摘Geobiology is a new discipline on the crossing interface between earth science and life science, and aims to understand the in- teraction and co-evolution between organisms and environments. On the basis of the latest international achievements, the new data presented in the Beijing geobiology forum sponsored by Chinese Academy of Sciences in 2013, and the papers in this special issue, here we present an overview of the progress and perspectives on three important frontiers, including geobiology of the critical periods in Earth history, geomicrobes and their responses and feedbacks to global environmental changes, and geobiology in extreme environments. Knowledge is greatly improved about the close relationship of some significant biotic events such as origin, radiation, extinction, and recovery of organisms with the deep Earth processes and the resultant envi- ronmental processes among oceans, land, and atmosphere in the critical periods, although the specific dynamics of the co-evolution between ancient life and paleoenvironments is still largely unknown. A variety of geomicrobial functional groups were found to respond sensitively to paleoenvironmental changes, which enable the establishment of proxies for paleoenvi- ronmental reconstruction, and to play active roles on the Earth environmental changes via elemental biogeochemical cycles and mineral bio-transforrnations, but to be deciphered are the mechanisms of these functional groups that change paleoenvi- ronmental conditions. Microbes of potential geobiology significance were found and isolated from some extreme environments with their biological properties partly understood, but little is known about their geobiological functions to change Earth envi- ronments. The biotic processes to alter or modify the environments are thus proposed to be the very issue geobiology aims to decipher in the future. Geobiology will greatly extend the temporal and spatial scope of biotic research on Earth and beyond. It has great potential of application in the domains of resource exploration and global change. To achieve these aims needs coor- dinative multidisciplinary studies concerning geomicrobiology and related themes, database and modeling of biogeochemical cycles, typical geological environments, and coupling of biological, physical, and chemical processes.
