The conversion of CO2 into H+ and is a relatively slow reaction. Hence, its kinetics may be rate determining in carbonate rock dissolution. Carbonic anhydrase (CA), which is widespread in nature, was used to catalyze ...The conversion of CO2 into H+ and is a relatively slow reaction. Hence, its kinetics may be rate determining in carbonate rock dissolution. Carbonic anhydrase (CA), which is widespread in nature, was used to catalyze the CO2 conversion process in dissolution experiments of limestone and dolomite. It was found that the rate of dissolution increases by a factor of about 10 after the addition of CA at a high CO2 partial pressure (Pco2) for limestone and about 3 at low Pco2 for dolomite. This shows that reappraisal is necessary for the importance of chemical weathering (including carbonate rock dissolution and silicate weathering) in the atmospheric CO2 sink and the mysterious missing sink in carbon cycling. It is doubtless that previous studies of weathering underestimated weathering rates due to the ignorance of CA as an activator in weathering, thus the contribution of weathering to the atmospheric CO2 sink is also underestimated. This finding also shows the need to examine the situ distribution and activity of CA in different waters and to investigate the role of CA in weathering.展开更多
Over the past three decades,the drawdown of atmospheric CO_(2) in vegetation and soil has fueled net ecosystem production(NEP).Here,a global land-surface model(CABLE)is used to estimate the trend in NEP and its respon...Over the past three decades,the drawdown of atmospheric CO_(2) in vegetation and soil has fueled net ecosystem production(NEP).Here,a global land-surface model(CABLE)is used to estimate the trend in NEP and its response to atmospheric CO_(2),climate change,biological nitrogen(N)fixation,and N deposition under future conditions from 2031 to 2100 in the Belt and Road region.The trend of NEP simulated by CABLE decreases from 0.015 Pg carbon(C)yr^(-2) under present conditions(1936–2005)to−0.023 Pg C yr^(-2) under future conditions.In contrast,the trend in NEP of the CMIP6 ensemble changes from 0.014 Pg C yr^(-2) under present conditions to−0.009 Pg C yr^(-2) under future conditions.This suggests that the trend in the C sink for the Belt and Road region will likely decline in the future.The significant difference in the NEP trend between present and future conditions is mainly caused by the difference in the impact of climate change on NEP.Considering the responses of soil respiration(RH)or net primary production(NPP)to surface air temperature,the trend in surface air temperature changes from 0.01℃ yr^(-1) under present conditions to 0.05℃ yr^(-1) under future conditions.CABLE simulates a greater response of RH to surface temperature than that of NPP under future conditions,which causes a decreasing trend in NEP.In addition,the greater decreasing trend in NEP under future conditions indicates that the C-climate-N interaction at the regional scale should be considered.It is important to estimate the direction and magnitude of C sinks under the C neutrality target.展开更多
湖泊沉积物碳通量是当前研究的重点内容,湖泊沉积物中无机碳主要以碳酸盐矿物的形式存在,而获取碳酸盐矿物中的无机碳含量的方法主要有X-射线衍射(XRD)法和酸溶后测定法两种。基于西藏色林错钻孔沉积物的X-射线衍射数据,估算了沉积物每...湖泊沉积物碳通量是当前研究的重点内容,湖泊沉积物中无机碳主要以碳酸盐矿物的形式存在,而获取碳酸盐矿物中的无机碳含量的方法主要有X-射线衍射(XRD)法和酸溶后测定法两种。基于西藏色林错钻孔沉积物的X-射线衍射数据,估算了沉积物每一种碳酸盐矿物和总无机碳的沉积碳通量,并与西藏及其他地区酸溶法的数据进行对比,发现XRD方法计算的沉积无机碳通量与酸溶法具有很好的一致性。湖泊沉积物中无机碳通量的问题本质上是碳酸盐矿物的成因问题,5000 a BP以来,色林错沉积的无机碳通量主要影响因素是干冷的气候,文石矿物含量决定了色林错沉积总无机碳通量的高低变化。展开更多
Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The ...Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation atmosphere.The theoretical validation was conducted through density functional calculations.The two gas molecules follow different pathways to increase the reactivity of char.CO_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups.Gas molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two effects.The synergism can be attributed to two possibilities.The inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional groups.Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.展开更多
Based on the theory of pH evolution of sea water and the balance between the seawater and the atmosphere the authors discussed the problems about (i) the method ofcalculating P_(CO_2) in the ancient atmosphere with th...Based on the theory of pH evolution of sea water and the balance between the seawater and the atmosphere the authors discussed the problems about (i) the method ofcalculating P_(CO_2) in the ancient atmosphere with the associations of sedimentary miner-als; (ii) the evolution of P_(CO_2) values in the geologic history; (iii) the relations of thepH evolution of sea water with carbonate precipitations; and (iv) calculation of the pHlimit for some associations of sedimentary minerals and its corresponding P_(CO_2) valuesin the atmosphere. The authors pointed out that though carbonates had deposited little in the Archaean,the content of CO_2 gas in the Archaean atmosphere was very high and was gradually go-ing up to form a thick CO_2 atmosphere. Up to 2600 Ma ago, the P_(CO_2) had reached a gradeof 10- 50 atm. There was a general trend of evolution that from the early Proterozoicera to the present the depositional horizon of carbonate layers was gradually risingand finally surpassed the horizons of clay minerals and sulfides. The corresponding P_(CO_2)in the atmosphere was lowering from the thick CO_2 atmosphere to the present 0.03%atm. On the basis of the calculated P_(CO_2) sizes and its fluctuation characteristics thehistory of P_(CO_2) evolution can be divided into three major stages.展开更多
Escalating threat of global warming and the steady growth in world population require the development of transformative greenhouse gas control technologies and food production systems of high energy efficiency,small e...Escalating threat of global warming and the steady growth in world population require the development of transformative greenhouse gas control technologies and food production systems of high energy efficiency,small environmental footprint and low cost.To control the global temperature rise below 2℃ by 2050,global greenhouse gas emissions need to be cut by more than 80%.At the same time,our land needs to be utilized more efficiently and productively in order to produce enough food to feed projected 9 billion people with less available land area for food production in 2050.We propose to develop a modern urban vertical farming system,i.e.greenhouses equipped with a Carbon Enrichment for Plant Stimulation(CEPS)system,to enhance land use efficiency and thus increase food productivity and,at the same time,to sequestrate CO_(2) from ambient air.The deployment of such a CEPS system will have a potential to remove more than 500 million tonnes CO_(2) from air annually,and increase the current food productivity by more than 15 times than the open field operation.The deployment of the CEPS technology will also promote locally produced food,benefiting urban economical development and job creation.展开更多
基金Financial supports for this research was provided by the National Nature Science Foundation of China(Grant 40073026)Ministry of Science and Technology of China(Grant 164)+1 种基金Natural Science Foundation of Guangxi(Grant 9824021)Ministry of Land and Resources of China(Grant 9806)and Bremen University of Germany.
文摘The conversion of CO2 into H+ and is a relatively slow reaction. Hence, its kinetics may be rate determining in carbonate rock dissolution. Carbonic anhydrase (CA), which is widespread in nature, was used to catalyze the CO2 conversion process in dissolution experiments of limestone and dolomite. It was found that the rate of dissolution increases by a factor of about 10 after the addition of CA at a high CO2 partial pressure (Pco2) for limestone and about 3 at low Pco2 for dolomite. This shows that reappraisal is necessary for the importance of chemical weathering (including carbonate rock dissolution and silicate weathering) in the atmospheric CO2 sink and the mysterious missing sink in carbon cycling. It is doubtless that previous studies of weathering underestimated weathering rates due to the ignorance of CA as an activator in weathering, thus the contribution of weathering to the atmospheric CO2 sink is also underestimated. This finding also shows the need to examine the situ distribution and activity of CA in different waters and to investigate the role of CA in weathering.
基金funded by the National Natural Science Foundation of China[grant numbers 41630532,41975112,42175142,and 42175013].
文摘Over the past three decades,the drawdown of atmospheric CO_(2) in vegetation and soil has fueled net ecosystem production(NEP).Here,a global land-surface model(CABLE)is used to estimate the trend in NEP and its response to atmospheric CO_(2),climate change,biological nitrogen(N)fixation,and N deposition under future conditions from 2031 to 2100 in the Belt and Road region.The trend of NEP simulated by CABLE decreases from 0.015 Pg carbon(C)yr^(-2) under present conditions(1936–2005)to−0.023 Pg C yr^(-2) under future conditions.In contrast,the trend in NEP of the CMIP6 ensemble changes from 0.014 Pg C yr^(-2) under present conditions to−0.009 Pg C yr^(-2) under future conditions.This suggests that the trend in the C sink for the Belt and Road region will likely decline in the future.The significant difference in the NEP trend between present and future conditions is mainly caused by the difference in the impact of climate change on NEP.Considering the responses of soil respiration(RH)or net primary production(NPP)to surface air temperature,the trend in surface air temperature changes from 0.01℃ yr^(-1) under present conditions to 0.05℃ yr^(-1) under future conditions.CABLE simulates a greater response of RH to surface temperature than that of NPP under future conditions,which causes a decreasing trend in NEP.In addition,the greater decreasing trend in NEP under future conditions indicates that the C-climate-N interaction at the regional scale should be considered.It is important to estimate the direction and magnitude of C sinks under the C neutrality target.
文摘湖泊沉积物碳通量是当前研究的重点内容,湖泊沉积物中无机碳主要以碳酸盐矿物的形式存在,而获取碳酸盐矿物中的无机碳含量的方法主要有X-射线衍射(XRD)法和酸溶后测定法两种。基于西藏色林错钻孔沉积物的X-射线衍射数据,估算了沉积物每一种碳酸盐矿物和总无机碳的沉积碳通量,并与西藏及其他地区酸溶法的数据进行对比,发现XRD方法计算的沉积无机碳通量与酸溶法具有很好的一致性。湖泊沉积物中无机碳通量的问题本质上是碳酸盐矿物的成因问题,5000 a BP以来,色林错沉积的无机碳通量主要影响因素是干冷的气候,文石矿物含量决定了色林错沉积总无机碳通量的高低变化。
基金supported by the CAS Project for Young Scientists in Basic Research(YSBR-028)。
文摘Adequate destruction of the aromatic structure in coal is key to further reducing the emission of pollutants.In this research,activation reactions of Shenmu coal powder were carried out in a vertical tube furnace.The study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation atmosphere.The theoretical validation was conducted through density functional calculations.The two gas molecules follow different pathways to increase the reactivity of char.CO_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional groups.Gas molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two effects.The synergism can be attributed to two possibilities.The inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional groups.Introducing oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.
文摘Based on the theory of pH evolution of sea water and the balance between the seawater and the atmosphere the authors discussed the problems about (i) the method ofcalculating P_(CO_2) in the ancient atmosphere with the associations of sedimentary miner-als; (ii) the evolution of P_(CO_2) values in the geologic history; (iii) the relations of thepH evolution of sea water with carbonate precipitations; and (iv) calculation of the pHlimit for some associations of sedimentary minerals and its corresponding P_(CO_2) valuesin the atmosphere. The authors pointed out that though carbonates had deposited little in the Archaean,the content of CO_2 gas in the Archaean atmosphere was very high and was gradually go-ing up to form a thick CO_2 atmosphere. Up to 2600 Ma ago, the P_(CO_2) had reached a gradeof 10- 50 atm. There was a general trend of evolution that from the early Proterozoicera to the present the depositional horizon of carbonate layers was gradually risingand finally surpassed the horizons of clay minerals and sulfides. The corresponding P_(CO_2)in the atmosphere was lowering from the thick CO_2 atmosphere to the present 0.03%atm. On the basis of the calculated P_(CO_2) sizes and its fluctuation characteristics thehistory of P_(CO_2) evolution can be divided into three major stages.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2022QZKK0101)the National Natural Science Foundation of China(41988101,42001104,and 41975140)+1 种基金the National Key Scientific and Technological Infrastructure Project“Earth System Science Numerical Simulator Facility”(Earth Lab,201715003471104355)the Innovation Program for Young Scholars of TPESER(TPESER-QNCX2022ZD-01)。
基金Supports from Fuzhou University through a MinJiang Scholar program and Natural Science and Engineering Research Council(NSERC)of Canada through a discovery program are gratefully acknowledged.
文摘Escalating threat of global warming and the steady growth in world population require the development of transformative greenhouse gas control technologies and food production systems of high energy efficiency,small environmental footprint and low cost.To control the global temperature rise below 2℃ by 2050,global greenhouse gas emissions need to be cut by more than 80%.At the same time,our land needs to be utilized more efficiently and productively in order to produce enough food to feed projected 9 billion people with less available land area for food production in 2050.We propose to develop a modern urban vertical farming system,i.e.greenhouses equipped with a Carbon Enrichment for Plant Stimulation(CEPS)system,to enhance land use efficiency and thus increase food productivity and,at the same time,to sequestrate CO_(2) from ambient air.The deployment of such a CEPS system will have a potential to remove more than 500 million tonnes CO_(2) from air annually,and increase the current food productivity by more than 15 times than the open field operation.The deployment of the CEPS technology will also promote locally produced food,benefiting urban economical development and job creation.
