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The current and future of terrestrial carbon balance over the Tibetan Plateau

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Science China Earth Sciences 2023年第7期66卷 1493-1503页

作者： Tao WANG Xiaoyi WANG Dan LIU Guanting LV Shuai REN Jinzhi DING Baozhang CHEN Jiansheng QU Yafeng WANG Shilong PIAO Fahu CHEN State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100101China State Key Laboratory of Resource and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Chengdu Documentation and Information Center Chinese Academy of SciencesChengdu 610041China Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100101China

The contemporary carbon balance over the Tibetan Plateau is highly uncertain with a ten-fold difference between various *** a warming world,the potential exists for a large carbon release from its permafrost which could compromise China’s 2060 carbon-neutral ***,we used a satellite-and inventory-based approach,ecosystem models,and atmospheric inversions to estimate that the carbon sink was 33.12–37.84 TgC yr^(–1)during 2000–*** carbon sink induced by climate change and increasing CO_(2) levels largely overcompensated for a livestock grazing-induced carbon source of 0.38TgC yr^(-1).By 2060,the carbon sink is projected to increase by 38.3–74.5% under moderate to high emissions scenarios,with the enhanced vegetation carbon uptake outweighing the warming-induced permafrost carbon *** restoration of degraded grassland could sequestrate an additional 9.06 TgC yr^(-1),leading to a total carbon sink of 57.78–70.52 TgC yr^(-1).We conclude that the Tibetan Plateau’s ecosystems absorbed two-and-a-half times the amount of its cumulative fossil CO_(2) emissions during 2000–2015 and that their carbon sinks will almost double in strength in the future,helping to achieve China’s pledge to become carbon neutral by 2060.

关键词： Tibetan Plateau carbon balance Satellite-and inventory-based approach Terrestrial ecosystem models Atmospheric inversions Grassland restoration

Long-term variability of the carbon balance in a large irrigated area along the lower Yellow River from 1984 to 2006

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Science China Earth Sciences 2013年第4期56卷 671-683页

作者： LEI HuiMin YANG DaWen CAI JianFeng WANG FengJiao State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University Management Office of the Weishan Irrigation District Binzhou Bureau of Meteorology

The irrigated areas in the northern region of China are important food production areas. Therefore, studies on the variability of the carbon balance in these agro-ecosystems are fundamental for the management of carbon sequestration. This paper simulated the long-term variability of the carbon balance in a typical irrigated area along the lower Yellow River from 1984 to 2006, using a process-based ecosystem model called the Simple Biosphere Model, version 2. The mean annual gross primary production (GPP), mean annual net assimilation rate (NAR), mean annual soil respiration (Rs ), and mean annual net ecosystem exchange (NEE) were 1733, 1642, 1304, and 338g C m-2 a-1 , respectively. A significant increasing trend in the seasonal total NAR during the wheat growing season, and a significant decreasing trend in the seasonal total NAR during the maize growing season were detected. However, no significant trend was found in the annual NAR, R s , and NEE. The average carbon sequestration was 1.93 Tg C a-1 when the grain harvest was not taken into account, and the carbon sequestration amount during the maize season was higher than that during the wheat season. However, the agro-ecosystem was a weak carbon source with a value of 0.23 Tg C a-1 , when the carbon in the grain was assumed emitted into the atmosphere.

关键词： carbon balance winter wheat summer maize process-based ecosystem model irrigated area

Soil carbon balance in a Native Temperate Grassland in the Xilin River Basin of Inner Mongolia

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Acta Botanica Sinica 2002年第6期44卷 740-742页

作者：李凌浩韩兴国王其兵白文明白永飞闫志丹陈全胜张焱杨晶李鑫宋世环中国科学院植物研究所植被数量生态学开放研究实验室北京100093

Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above-ground biomass production was 79.8 g C(.)m(-2.)a(-1), and from root biomass to 30 cm. depth averaged 311.9 g C(.)m(-2.)a(-1). The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C(.)m(-2.)a(-1). 2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C(.)m(-2.)a(-1), and the carbon output by leaching or light-chemical oxidation was 3.2 g C(.)m(-2.)a(-1) The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C(.)m(-2.)a(-1), and the summed mean annual output was approximately 364.8 g C(.)m(-2.)a(-1). 3) A mature, steady-state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C(.)m(-2.)a(-1). Based on the soil organic carbon density of the field, the turnover Irate of soil carbon in 0 - 30 cm depth was calculated to be 6.2%, with a turnover time of 16 years.

关键词： Leymus chinensis steppe carbon balance soil respiration turnover rate net primary productivity (NPP)

Conversion characteristics and mechanism analysis of gaseous dichloromethane degraded by a VUV light in different reaction media

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Journal of Environmental Sciences 2012年第10期24卷 1777-1784页

作者： Jianming Yu Wenji Cai Jianmeng Chen Li Feng Yifeng Jiang Zhuowei Cheng .College of Biological and Environmental Engineering Zhefiang University of Technology Hangzhou 310032 China Environmental Science and Engineering Research Institute Zhefiang University of Technology Hangzhou 310032 China

The photodegradation of gaseous dichloromethane （DCM） by a vacuum ultraviolet （VUV） light in a spiral reactor was investigated with different reaction media and initial concentrations. Through the combination of direct photolysis, O3 oxidation and HO. oxidation, DCM was ultimately mineralized into inorganic compounds （such as HC1, CO2, H20, etc.） in the air with relative humidity （RH） of 75%-85%. During the photodegradation process, some small organic acids （including formic acid, acetic acid） were also detected and the intermediates were more soluble than DCM, providing a possibility for its combination with subsequent biodegradation. Based on the detected intermediates and the confirmed radicals, a photodegradation pathway of DCM by VUV was proposed. With RH 75%- 80% air as the reaction medium, the DCM removal followed the second-order kinetic model at inlet concentration of 100-1000 mg/m3. Kinetic analysis showed that the reaction media affected the kinetic constants of DCM conversion by a large extent, and RH 80% air could cause a much lower half-life for its conversion. Such results supported the possibility that VUV photodegradation could be used not only for the mineralization of DCM but also as a pretreatment before biodegradation.

关键词： dichloromethane VUV photodegradation mechanism carbon balance kinetic analysis

Degradation of dichloromethane by an isolated strain Pandoraea pnomenusa and its performance in a biotrickling filter

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Journal of Environmental Sciences 2014年第5期26卷 1108-1117页

作者： Jianming Yu Wenji Cai Zhuowei Cheng Jianmeng Chen Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals Zhejiang University of Technology College of Biological and Environmental Engineering Zhejiang University of Technology

A strain Pandoraea pnomenusa LX-1 that uses dichloromethane （DCM） as sole carbon and energy source has been isolated and identified in our laboratory. The optimum aerobic biodegradation of DCM in batch culture was evaluated by response surface methodology. Maximum biodegradation （5.35 mg/（***）） was achieved under cultivation at 32.8℃, pH 7.3, and 0.66% NaC1. The growth and biodegradation processes were well fitted by Haldane＇s kinetic model, yielding maximum specific growth and degradation rates of 0.133 hr^-1 and 0.856 hr^-1, respectively. The microorganism efficiently degraded a mixture of DCM and coexisting components （benzene, toluene and chlorobenzene）. The carbon recovery （52.80%-94.59%） indicated that the targets were predominantly mineralized and incorporated into cell materials. Electron acceptors increased the DCM biodegradation rate in the following order： mixed 〉 oxygen 〉 iron 〉 sulfate 〉 nitrate. The highest dechlorination rate was 0.365 mg C1-/（*** biomass）, obtained in the presence of mixed electron acceptors. Removal was achieved in a continuous biotrickling filter at 56%-85% efficiency, with a mineralization rate of 75.2%. Molecular biology techniques revealed the predominant strain as P. pnomenusa LX-1. These results clearly demonstrated the effectiveness of strain LX-1 in treating DCM-containing industrial effluents. As such, the strain is a strong candidate for remediation of DCM coexisting with other organic compounds.

关键词： dichloromethane Pandoraea pnomenusa biodegradation characteristics removal performance carbon balance

carbon forestry is surprising

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Forest Ecosystems 2018年第2期5卷 140-150页

作者： Timo Pukkala University of Eastern Finland PO Box 111 80101 Joensuu Finland

Background： Forestry offers possibilities to sequestrate carbon in living biomass, deadwood and forest soil, as we as in products prepared of wood. In addition, the use of wood may reduce carbon emissions from fossil fuels. However, harvesting decreases the carbon stocks of forests and increases emissions from decomposing harvest residues. Methods： This study used simulation and optimization to maximize carbon sequestration in a boreal forest estate consisting of nearly 600 stands. A reference management plan maximized net present value and the other plans maximized the total carbon balance of a 100-, 200- or 300-year planning horizon, taking into account the carbon balances of living forest biomass, dead organic matter, and wood-based products Results： Maximizing carbon balance led to low cutting level with all three planning horizons. Depending on the time span, the carbon balance of these schedules was 2 to 3.5 times higher than in the plan that maximized net present value. It was not optimal to commence cuttings when the carbon pool of living biomass and dead organic matter stopped increasing after 150-200 years. Conclusions： Letting many mature trees to die was a better strategy than harvesting them when the aim was to maximize the long-term carbon balance of boreal Fennoscandian forest. The reason for this conclusion was that large dead trees are better carbon stores than harvested trees. To alter this outcome, a higher proportion of harvested trees should be used for products in which carbon is stored for long time.

关键词： carbon balance carbon sequestration Decomposition model Wood product model Boreal forest

Divergent allocations of nonstructural carbohydrates shape growth response to rainfall reduction in two subtropical plantations

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Forest Ecosystems 2022年第2期9卷 222-233页

作者： Xinwei Guo Shirong Liu Hui Wang Zhicheng Chen Jinglei Zhang Lin Chen Xiuqing Nie Lu Zheng Daoxiong Cai Hongyan Jia Baoliang Niu Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijing100091China Experimental Center of Tropical Forestry Chinese Academy of ForestryPingxiang532600China Youyiguan Forest Ecosystem Research Station Pingxiang532600China

Nonstructural carbohydrates(NSC)are indicators of tree carbon balance and play an important role in regulating plant growth and ***,our understanding of the mechanism underlying drought-induced response of NSC reserves remains ***,we conducted a long-term throughfall exclusion(TFE)experiment to investigate the seasonal responses of NSC reserves to manipulative drought in two contrasting tree species(a broadleaved tree Castanopsis hystrix *** a coniferous tree Pinus massoniana Lamb.)of the subtropical *** found that in the dry season,the two tree species differed in their responses of NSC reserves to TFE at either the whole-tree level or by organs,with significantly depleted total NSC reserves in roots in both *** the TFE treatment,there were significant increases in the NSC pools of leaves and branches in ***,which were accompanied by significant decreases in fine root biomass and radial growth without significant changes in canopy photosynthesis;while *** exhibited significant increase in fine root biomass without significant changes in radial *** results suggested that under prolonged water limitation,NSC usage for growth in *** is somewhat impaired,such that the TFE treatment resulted in NSC accumulation in aboveground organs(leaf and branch);whereas *** is capable of efficiently utilizing NSC reserves to maintain its growth under drought *** findings revealed divergent NSC allocations under experimental drought between the two contrasting tree species,which are important for better understanding the differential impacts of climate change on varying forest trees and plantation types in subtropical China.

关键词： Photosynthesis carbon balance Tree growth Nonstructural carbohydrates carbon limitation

Dark respiration in the light and in darkness of three marine macroalgal species grown under ambient and elevated CO_2 concentrations

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Acta Oceanologica Sinica 2011年第1期30卷 106-112页

作者： ZOU Dinghui GAO Kunshan XIA Jianrong College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of Education Guangzhou 510006 China State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China College of Environmental Science and Engineering Guangzhou University Guangzhou 510006 China

Dark respiration （non-photorespiratory mitochondrial respiration）, which occurs both in the light and in darkness, is vital for growth and survival of algae and plays a critical role in modulating the carbon balance of them. In the present study, we have investigated dark respiration in the light （RL） and in darkness （RD） in three marine macroalgal species, Hizikia fusiformis （phaeophyta）, Gracilaria lemaneiformis （Rhodophyta） and Ulva lactuca （Chlorophyta）, cultured at 20 ℃ using aeration with two CO2 conditions： current ambient （CO2 concentration about 380 μl/L） and elevated CO2 （approximately 720 μl/L） air. RL was estimated by using the Kok method, whereas RD was determined as the rate of O2 influx at zero light. The results showed that both RL and RD were unchanged for the elevated CO2-grown algae relative to ambient CO2 concentration for all the algal species tested. However, RL was significantly lower than RD across all the algal species and growth CO2 treatments, demonstrating that daytime respiration was partly depressed by the light. The percentage of inhibition of respiration by light was similar between ambient and elevated CO2- grown algae. The ratio of respiration to photosynthesis, which tended to decrease when estimated using RL instead of RD, was not altered for the elevated relative to ambient CO2 concentration. The results suggest that RL, rather than RD, is a more accurate estimate of nonphotorespiratory carbon loss in marine macroalgae during the daytime. It would not be anticipated that elevated atmospheric CO2 would exert a substantial influence on respiratory flux either in the light or in darkness in these particular marine macroalgal species.

关键词： marine macroalgae respiration CO2 carbon balance

Reconciliation of research on forest carbon sequestration and water conservation

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Journal of Forestry Research 2021年第1期32卷 7-14页

作者： Tanzeel Javaid Aini Farooqi Xuhua Li Zhen Yu Shirong Liu Osbert Jianxin Sun School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083People’s Republic of China Sichuan Academy of Forestry Chengdu 610081People’s Republic of China School of Applied Meteorology Nanjing University of Information Science and TechnologyNanjing 210044People’s Republic of China State Forestry and Grassland Administration of China Key Laboratory of Forest Ecology and Environment Institute of Forest EcologyEnvironment and ProtectionChinese Academy of ForestryBeijing 100091People’s Republic of China

carbon sequestration and water conservation are two of the key ecosystem services that forests provide for societal need to address environmental *** of the dual services is the ultimate goal in forest management for mitigating global climate change and safeguarding terrestrial water ***,there are some tradeoff s between gain in forest productivity and ecosystem water *** conducted literature review based on published articles for learned knowledge on forest carbon fi xation and hydrological *** knowledge gaps and research needs are identifi ed by examining the inter-connections between forest carbon sequestration and water *** researches have helped gain basic understanding of the mechanisms and controls of forest carbon fi xation and hydrological regulations as two separate *** and approaches are well established for quantifying and monitoring forest carbon and hydrological issues,operating at diff erent spatial and temporal *** are knowledge gaps on how to design aff orestation schemes facilitating enhanced ecosystem services in forest carbon sequestration and water *** the top-down planning of aff orestation in regions where water availability is anticipated to be problematic,the questions of how much and where to plant for given land availability,known environmental implications,and sustained regional development and livelihood need to be *** local management considerations,the questions of what and how to plant *** orts are needed in joint studies of forest carbon sequestration and water conservation functionalities,specifi cally in relation to establishment and management of planted forests aiming for delivering regulatory ecosystem services in carbon sequestration,water conservation and other social *** propose an integrated framework with dual consideration of carbon sequestration and water conservation in forest management for future researc

关键词： carbon balance Ecosystem services Forest management Hydrological processes Tradeoff