Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matt...Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter(AOC).However,the mechanisms underlying BCP and the amount of generated AOC deposited effectively,are still poorly understood.Therefore,we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake(Yunnan,SW China),the second-deepest plateau,oligotrophic freshwater lake in China.Temperature,pH,EC(electrical conductivity),DO(dissolved O2),[HCO3^-],[Ca^2+],SIc,partial CO2(pCO2)pressure,and carbon isotopic compositions of HCO3^-(δ^13CDIc)in water from Fuxian Lake all displayed distinct seasonal and vertical variations.This was especially apparent in an inverse correlation between pCO2 and DO,indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs.Furthermore,the lowest C/N ratios and highestδ^13Corg were recorded in the trap sediments.Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30%to 100%of all OC,indicating that AOC was an important contributor to sedimentary organic matter(OC).It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km^-2 in 2017.Therefore,AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle.展开更多
Heavy metal pollution can lead to a great loss of soil organic carbon(SOC).However,the microbial mechanisms that link heavy metal pollution to SOC remain poorly understood.Here,we investigated five apple-orchard soils...Heavy metal pollution can lead to a great loss of soil organic carbon(SOC).However,the microbial mechanisms that link heavy metal pollution to SOC remain poorly understood.Here,we investigated five apple-orchard soils at different distances from a Pb-Zn smelter.After assessing the heavy metal pollution level based on Grade Ⅱ of the national soil environmental quality standard(China),we found SOC stocks and microbial carbon pump(MCP)capacity(i.e.,microbial residue carbon)under medium and heavy pollution levels were significantly lower than those under safe,cordon and light pollution levels.The structural equation model showed causality in the SOC variations linked to pollution level through MCP capacity,which could contribute 77.8% of the variance in SOC storage.This verified MCP capacity can serve as a key parameter for evaluation of SOC storage under heavy metal pollution.Soil MCP efficacy,i.e.,the proportion of microbial residue carbon to SOC,also decreased under medium and heavy pollution.This suggested that,with a heavier pollution level,there was a higher rate of reduction of microbial residue carbon in soil than the rate of reduction of SOC.As MCP efficacy can be a useful assessment of SOC stability,the significantly positive relationship between MCP efficacy and clay content in correlation analysis implied that lower MCP efficacy was correlated with SOC stability under the heavier pollution level.Our study provides valuable insights to identify the mechanisms of microbially mediated C transformation processes that are influenced by heavy metal pollution in agroecosystems.展开更多
Soil is a huge terrestrial carbon pool, which has higher carbon storage than the sum of atmospheric and terrestrial vegetation carbon. Small fluctuations in soil carbon pool can affect regional carbon flux and global ...Soil is a huge terrestrial carbon pool, which has higher carbon storage than the sum of atmospheric and terrestrial vegetation carbon. Small fluctuations in soil carbon pool can affect regional carbon flux and global climate change. As soil organic carbon plays key roles in soil carbon storage and sequestration, studying its composition, sources and stability mechanism is a key to deeply understand the functions of terrestrial ecosystem and how it will respond to climate changes. The recently-proposed concept of soil Microbial Carbon Pump(MCP) emphasizes the importance of soil microbial anabolism and its contributions to soil carbon formation and stabilization, which can be applied for elucidating the source, formation and sequestration of soil organic carbon. This article elaborates MCP-mediated soil carbon sequestration mechanism and its influencing factors, as well as representative scientific questions we may explore with the soil MCP conceptual framework.展开更多
The soil microbial carbon pump(MCP)conceptualizes a sequestration mechanism based on the process of microbial production of a set of new organic compounds,which carry the carbon from plant,through microbial anabolism,...The soil microbial carbon pump(MCP)conceptualizes a sequestration mechanism based on the process of microbial production of a set of new organic compounds,which carry the carbon from plant,through microbial anabolism,and enter into soil where it can be stabilized by the entombing effect.Understanding soil MCP and its related entombing effect is essential to the stewardship of ecosystem services,provided by microbial necromass in the formation and stabilization of soil organic matter as well as its resilience and vulnerability to global change.The mechanism and appraisal of soil MCP,however,remain to be elucidated.This lack of knowledge hampers the improvement of climate models and the development of land use policies.Here,I overview available knowledge to provide insights on the nature of the soil MCP in the context of two main aspects,i.e.,internal features and external constraints that mechanistically influence the soil MCP operation and ultimately influence microbial necromass dynamics.The approach of biomarker amino sugars for investigation of microbial necromass and the methodological limitations are discussed.Finally,I am eager to call new investigations to obtain empirical data in soil microbial necromass research area,which urgently awaits synthesized quantitative and modeling studies to relate to soil carbon cycling and climate change.展开更多
The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this ...The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this study, we developed a coupled physical-ecosystem model with major MCP processes in the South China Sea(SCS). The model estimated a SCSaveraged MCP rate of 1.55 mg C m^(-2) d^(-1), with an MCP-to-BP ratio of 1:6.08 when considering the BP at a depth of 1000 m.Moreover, the ecosystem responses were projected in two representative global warming scenarios where the sea surface temperature increased by 2 and 4°C. The projection suggested a declined productivity associated with the increased near-surface stratification and decreased nutrient supply, which leads to a reduction in diatom biomass and consequently the suppression of the BP. However, the relative ratio of picophytoplankton increased, inducing a higher microbial activity and a nonlinear response of MCP to the increase in temperature. On average, the ratio of MCP-to-BP at a 1000-m depth increased to 1:5.95 with surface warming of 4°C, indicating the higher impact of MCP in future ocean carbon sequestration.展开更多
It has been proposed that photosynthetic plankton can be used as a biological carbon pump tp absorb and sequester carbon dioxide in the ocean.In this paper,plankton population dynamics are simulated in a single strati...It has been proposed that photosynthetic plankton can be used as a biological carbon pump tp absorb and sequester carbon dioxide in the ocean.In this paper,plankton population dynamics are simulated in a single stratified water column to predict carbon dioxide sequestering due to surface iron fertilization in deep ocean.Using a predator-prey model and realistic parameter values,iron fertilization was found to only cause temporary blooms up to 5 months in duration,and relatively small increases in adsorption of atmospheric CO_(2).展开更多
Carbon dioxide trans-critical heat pump system for heating and cooling water was designed,and its thermodynamic steady-state concentration model was established. Based on the steady-state model,parameters of the carbo...Carbon dioxide trans-critical heat pump system for heating and cooling water was designed,and its thermodynamic steady-state concentration model was established. Based on the steady-state model,parameters of the carbon dioxide trans-critical heat pump were calculated by computer programming. According to these parameters,the effects and application prospect of the heat pump system were analyzed for dual-temperature drinking fountains.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 41430753, U1612441)
文摘Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter(AOC).However,the mechanisms underlying BCP and the amount of generated AOC deposited effectively,are still poorly understood.Therefore,we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake(Yunnan,SW China),the second-deepest plateau,oligotrophic freshwater lake in China.Temperature,pH,EC(electrical conductivity),DO(dissolved O2),[HCO3^-],[Ca^2+],SIc,partial CO2(pCO2)pressure,and carbon isotopic compositions of HCO3^-(δ^13CDIc)in water from Fuxian Lake all displayed distinct seasonal and vertical variations.This was especially apparent in an inverse correlation between pCO2 and DO,indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs.Furthermore,the lowest C/N ratios and highestδ^13Corg were recorded in the trap sediments.Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30%to 100%of all OC,indicating that AOC was an important contributor to sedimentary organic matter(OC).It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km^-2 in 2017.Therefore,AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle.
基金supported by the Natural Science Foundation of Shandong Province(ZR2019PD022)the Central Public-interest Scientific Institution Basal Research Fund(FIRI20210401)the Major Scientific and Technological Innovation Projects of Key Research and Development Program in Shandong Province(2019JZZY010717).
文摘Heavy metal pollution can lead to a great loss of soil organic carbon(SOC).However,the microbial mechanisms that link heavy metal pollution to SOC remain poorly understood.Here,we investigated five apple-orchard soils at different distances from a Pb-Zn smelter.After assessing the heavy metal pollution level based on Grade Ⅱ of the national soil environmental quality standard(China),we found SOC stocks and microbial carbon pump(MCP)capacity(i.e.,microbial residue carbon)under medium and heavy pollution levels were significantly lower than those under safe,cordon and light pollution levels.The structural equation model showed causality in the SOC variations linked to pollution level through MCP capacity,which could contribute 77.8% of the variance in SOC storage.This verified MCP capacity can serve as a key parameter for evaluation of SOC storage under heavy metal pollution.Soil MCP efficacy,i.e.,the proportion of microbial residue carbon to SOC,also decreased under medium and heavy pollution.This suggested that,with a heavier pollution level,there was a higher rate of reduction of microbial residue carbon in soil than the rate of reduction of SOC.As MCP efficacy can be a useful assessment of SOC stability,the significantly positive relationship between MCP efficacy and clay content in correlation analysis implied that lower MCP efficacy was correlated with SOC stability under the heavier pollution level.Our study provides valuable insights to identify the mechanisms of microbially mediated C transformation processes that are influenced by heavy metal pollution in agroecosystems.
基金support from the EcoMicrobiology Lab and Soil and Environmental Biochemistry Lab in the Institute of Applied Ecology, Chinese Academy of Sciencessupported by the National Natural Science Foundation of China (Grant Nos. 31930070 & 41977051)。
文摘Soil is a huge terrestrial carbon pool, which has higher carbon storage than the sum of atmospheric and terrestrial vegetation carbon. Small fluctuations in soil carbon pool can affect regional carbon flux and global climate change. As soil organic carbon plays key roles in soil carbon storage and sequestration, studying its composition, sources and stability mechanism is a key to deeply understand the functions of terrestrial ecosystem and how it will respond to climate changes. The recently-proposed concept of soil Microbial Carbon Pump(MCP) emphasizes the importance of soil microbial anabolism and its contributions to soil carbon formation and stabilization, which can be applied for elucidating the source, formation and sequestration of soil organic carbon. This article elaborates MCP-mediated soil carbon sequestration mechanism and its influencing factors, as well as representative scientific questions we may explore with the soil MCP conceptual framework.
基金supported by the National Natural Science Foundation of China(No.31930070,41977051)the K.C.Wong Education Foundation of China(No.GJTD-2019-10)the Alexander von Humboldt Foundation of Germany are also acknowledged with gratitude.
文摘The soil microbial carbon pump(MCP)conceptualizes a sequestration mechanism based on the process of microbial production of a set of new organic compounds,which carry the carbon from plant,through microbial anabolism,and enter into soil where it can be stabilized by the entombing effect.Understanding soil MCP and its related entombing effect is essential to the stewardship of ecosystem services,provided by microbial necromass in the formation and stabilization of soil organic matter as well as its resilience and vulnerability to global change.The mechanism and appraisal of soil MCP,however,remain to be elucidated.This lack of knowledge hampers the improvement of climate models and the development of land use policies.Here,I overview available knowledge to provide insights on the nature of the soil MCP in the context of two main aspects,i.e.,internal features and external constraints that mechanistically influence the soil MCP operation and ultimately influence microbial necromass dynamics.The approach of biomarker amino sugars for investigation of microbial necromass and the methodological limitations are discussed.Finally,I am eager to call new investigations to obtain empirical data in soil microbial necromass research area,which urgently awaits synthesized quantitative and modeling studies to relate to soil carbon cycling and climate change.
基金supported by the National Basic Research Program (Grant No. 2013CB955704)the National Program on Global Change and Air-Sea Interaction (Grant No. GASI-03-01-02-05)+1 种基金partially supported by the SOA Global Change and Air-Sea Interaction Project (Grant No. GASI-IPOVAI-01–04)the National Natural Science Foundation of China (Grant Nos. 41630963, 41476007 & 41476005)
文摘The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this study, we developed a coupled physical-ecosystem model with major MCP processes in the South China Sea(SCS). The model estimated a SCSaveraged MCP rate of 1.55 mg C m^(-2) d^(-1), with an MCP-to-BP ratio of 1:6.08 when considering the BP at a depth of 1000 m.Moreover, the ecosystem responses were projected in two representative global warming scenarios where the sea surface temperature increased by 2 and 4°C. The projection suggested a declined productivity associated with the increased near-surface stratification and decreased nutrient supply, which leads to a reduction in diatom biomass and consequently the suppression of the BP. However, the relative ratio of picophytoplankton increased, inducing a higher microbial activity and a nonlinear response of MCP to the increase in temperature. On average, the ratio of MCP-to-BP at a 1000-m depth increased to 1:5.95 with surface warming of 4°C, indicating the higher impact of MCP in future ocean carbon sequestration.
文摘It has been proposed that photosynthetic plankton can be used as a biological carbon pump tp absorb and sequester carbon dioxide in the ocean.In this paper,plankton population dynamics are simulated in a single stratified water column to predict carbon dioxide sequestering due to surface iron fertilization in deep ocean.Using a predator-prey model and realistic parameter values,iron fertilization was found to only cause temporary blooms up to 5 months in duration,and relatively small increases in adsorption of atmospheric CO_(2).
基金Project(08YZ96) supported by the Innovation Program of Shanghai Municipal Education Commission,ChinaProject(J50502) supported by the Leading Academic Discipline Project of Shanghai Municipal Education Commission, ChinaProject supported by "Man Heng" Innovation Fund Project of University of Shanghai for Science and Technology
文摘Carbon dioxide trans-critical heat pump system for heating and cooling water was designed,and its thermodynamic steady-state concentration model was established. Based on the steady-state model,parameters of the carbon dioxide trans-critical heat pump were calculated by computer programming. According to these parameters,the effects and application prospect of the heat pump system were analyzed for dual-temperature drinking fountains.
