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Rainfall pulse response of carbon exchange to the timing of natural intra-annual rainfall in a temperate grass ecosystem

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ECOLOGICAL INDICATORS 2020年 118卷 106730-106730页

作者： Hao, Guangcun Hu, Zhongmin Di, Kai Li, Shenggong South China Normal Univ Sch Geog Guangzhou 510631 Peoples R China Southern Marine Sci & Engn Guangdong Lab Zhuhai 519082 Peoples R China Guang Dong Res Ctr Smart Homeland Engn Guangzhou 510631 Peoples R China Chinese Acad Sci Key Lab Ecosyst Network Observat & Modeling Synth Res Ctr Chinese Ecosystem Res Network Inst Geog Sci & Nat Resources Res Beijing Peoples R China Univ Chinese Acad Sci Coll Resources & Environm Beijing Peoples R China

Rainfall pulses play a key role in dominating the ecosystem carbon balance in arid and semiarid regions. In the future, the intensity and frequency of rainfall events will be significantly altered. Therefore, discussing the response of the carbon balance to rainfall pulses is extremely important for predicting the effect of global change on the carbon cycle. In grasslands, previous studies have documented that there is a threshold of rainfall size, above which net ecosystem exchange (NEE) would shift from positive (carbon source) to negative (carbon sink). However, does this threshold exist under altered intra-annual rainfall timing during growing season? To answer this question, we conducted an experiment in a typical grassland ecosystem to detect the relationship between rainfall pulse and carbon balance during the growing seasons from 2012 to 2015. Our studies showed that there was no rainfall threshold for the NEE from carbon source to sink with the change in rainfall timing. In the early growing season, there was a positive relationship (carbon source) between the NEE and rainfall pulses. In the middle growing season, there was a negative relationship (carbon sink) between the NEE and rainfall pulses. Moreover, the response magnitude of the NEE was positively related to the activity duration differences between ecosystem respiration (ER) and gross primary productivity (GPP). This study provided a new perspective on the proximate causes of the effects of rainfall on NEE. The mechanism underlying the response patterns of NEE to rainfall pulses is of critical importance for improving our ability to project future changes in the Earth system.

关键词： Climate change Rainfall pattern Grassland ecosystem carbon balance

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Specific Responses of Soil Microbial Residue Carbon to Long-Term Mineral Fertilizer Applications to Reddish Paddy Soils

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Pedosphere 2018年第3期28卷 488-496页

作者： ZHANG Xinyu XIE Juan YANG Fengting DONG Wenyi DAI Xiaoqin YANG Yang SUN Xiaomin Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences Beijing 100101( China) College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190( China) Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing 100081(China)

Mineral nutrient inputs to soil may alter microbial activity and consequently influence the accumulation of microbial residues. In this study, we investigated the effects of application rates and ratios of mineral fertilizers on the microbial residue carbon(MRC) of reddish paddy soils after long-term(15-year) fertilizer applications in southern China. Contents of three soil amino sugars as microbial residue contents were determined and MRC were calculated based on amino sugars. Results showed that three individual amino sugar contents increased as fertilizer application rates increased until maximum values were reached at a rate of 450-59-187 kg ha^(-1) year^(-1)(N-P-K). The three amino sugar contents then declined significantly under the highest mineral fertilizer application rate of 675-88-280 kg ha^(-1) year^(-1)(N-P-K). In addition, to enhance the microbial residue contents, it was more beneficial to double P(N:P:K= 1:0.26:0.41) in fertilizers applied to the P-deficient reddish paddy soils than to double either N(N:P:K = 2:0.13:0.41) or K(N:P:K= 1:0.13:0.82). The contents of the three individual amino sugars and microbial residues under different fertilizer application rates and ratios were significantly and positively correlated with soil organic carbon(SOC), total N, total P, and p H. Increases in values of the fungal C to bacterial C ratios showed that soil organic matter(SOM) stability increased because of the fertilizer applications over the past 15 years. The contents and ratios of amino sugars can be used as indicators to evaluate the impact of mineral fertilizer applications on SOM dynamics in subtropical paddy soils. The results indicated that fertilizer applications at a rate of 450-59-187 kg ha^(-1) year^(-1)(N-P-K) may improve crop yields, SOC contents, and SOC stability in subtropical paddy soils.

关键词： amino sugar application rate application ratio bacterial C fungal C soil nutrient soil organic C

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Hydrologic implications of the isotopic kinetic fractionation of open-water evaporation

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Science China Earth Sciences 2018年第10期61卷 1523-1532页

作者： Wei XIAO Yufei QIAN Xuhui LEE Wei WANG Mi ZHANG Xuefa WEN Shoudong LIU Yongbo HU Chengyu XIE Zhen ZHANG Xuesong ZHANG Xiaoyan ZHAO Fucun ZHANG Yale-NUIST Center on Atmospheric Environment & Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science & Technology School of Forestry and Environmental Studies Yale University Jiangsu Key Laboratory of Agricultural Meteorology Nanjing University of Information Science & Technology Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences

The kinetic fractionation of open-water evaporation against the stable water isotope H_2 ^(18)O is an important mechanism underlying many hydrologic studies that use ^(18)O as an isotopic tracer. A recent in-situ measurement of the isotopic water vapor flux over a lake indicates that the kinetic effect is much weaker(kinetic factor 6.2‰) than assumed previously(kinetic factor14.2‰) by lake isotopic budget studies. This study investigates the implications of the weak kinetic effect for studies of deuterium excess-humidity relationships, regional moisture recycling, and global evapotranspiration partitioning. The results indicate that the low kinetic factor is consistent with the deuterium excess-humidity relationships observed over open *** moisture recycling rate in the Great Lakes region derived from the isotopic tracer method with the low kinetic factor is a much better agreement with those from atmospheric modeling studies than if the default kinetic factor of 14.2‰ is used. The ratio of transpiration to evapotranspiration at global scale decreases from 84±9%(with the default kinetic factor) to 76±19%(with the low kinetic factor), the latter of which is in slightly better agreement with other non-isotopic partitioning results.

关键词： Kinetic fractionation factor Craig-Gordon model Moisture recycling Evapotranspiration partitioning Deuteriumexcess

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Modelling Soil Greenhouse Gas Fluxes from a Broad-leaved Korean Pine Forest in Changbai Mountain: Forest-DNDC Model Validation

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Journal of Resources and Ecology 2019年第2期10卷 127-136页

作者： YE Shu GUO Chuying HAN Jiayin ZHANG Leiming DAI Guanhua WEN Xuefa YU Guirui Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academyof Sciences Beijing 100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190 China Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China

Fluctuations in soil greenhouse gas(GHG)are an important part of the terrestrial ecosystem carbon-nitrogen cycle,but uncertainties remain about the dynamic change and budget assessment of soil GHG *** high frequency and consecutive soil GHG fluxes measured with an automatic dynamic chamber system,we tested the applicability of the current Forest-DNDC model in simulating soil CH4,CO2 and N2O fluxes in a temperate broad-leaved Korean pine forest at Changbai *** results showed that the Forest-DNDC model reproduced general patterns of environmental variables,however,simulated seasonal variation in soil temperature,snow melt processes and soil moisture partly deviated from measured variables,especially during the non-growing *** modeled CH4 flux was close to the field measurement and co-varied mainly with soil temperature and *** modeled soil CO2 flux had the same seasonal trend to that of the observation along with variation in temperature,however,simulated CO2 flux in the growing season was *** modeled N2O flux attained a peak in summer due to the influence of temperature,which was apparently different from the observed peak of N2O flux in the freeze-thaw ***,both modeled CO2 flux and N2O flux were dampened by rainfall *** from consistent estimation of annual soil CH4 flux,the annual accumulation of CO2 and N2O was *** is still necessary to further optimize model parameters and processes using long-term high-frequency observation data,especially transference of heat and water in soil and GHG producing *** work will improve modeling,ecosystem carbon-nitrogen budget assessment and estimation of soil GHGs flux from the site to the region.

关键词： soil GHGs flux dynamic chamber method forest-DNDC temperate forest

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Impact of environmental factors on water quality at multiple spatial scales and its spatial variation in Huai River Basin, China

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Science China Earth Sciences 2018年第1期61卷 82-92页

作者： XIA Jun WANG LongFeng YU JingJie ZHAN CheSheng ZHANG YongYong QIAO YunFeng WANG YueLing Key Laboratory of Water Cycle & Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Belting 100049 China State Key Laboratory of Water Resources & Hydropower Engineering Science Wuhan University Wuhan 430072 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Quantitative assessment of water quality and its spatial variation identification, as well as the discernment of primary factors affecting water quality are in its urgent in water environment management. In this study, four key water quality indicators,namely, ammonia nitrogen(NH_4^+-N), permanganate index(COD_(Mn)), total phosphorus(TP) and total nitrogen(TN) at 71 sampling sites were selected to evaluate water quality and its spatial variation identification. More concerns were emphasized on the anthropogenic factors(land use pattern) and natural factors(river density, elevation and precipitation) to quantify the overall water quality variations at different spatial scales. Results showed that the Yi-Shu-Si River sub-basin had a better water quality status than the Huai River sub-basin. The moderate polluted area nearly distributed in the upper and middle reaches of the Shaying River and Guo River. The high cluster centers which were surrounded with COD_(Mn), NH_4^+-N, TN and TP mainly also distributed in the upper and middle reaches of the Shaying River and Guo River. Redundancy analysis showed that the 200 m buffer area acted as the most sensitive area, which was easily subjected to pollution. The precipitation was identified as the most important variables among all the studied hydrological units, followed by farmland, urban land or elevation. The point source pollution was still existed although the non-point source pollution was also identified. The urban surface runoff pollution was severer than farmland fertilizer loss at the sub-basin scale in flood season, while the farmland showed "small-scale" effects for explaining overall water quality variations. This research is helpful for identifying the overall water quality variations from the scale-process interactions and providing a scientific basis for pollution control and decision making for the Huai River Basin.

关键词： Fuzzy comprehensive assessment Environmental factors Moran＇s I Redundancy analysis Pearson＇s correlation analysis Huai River Basin

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Longer conserved alpine forests ecosystem exhibits higher stability to climate change on the Tibetan Plateau

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Journal of Plant Ecology 2019年第4期12卷 645-652页

作者： Jian Li Nan Cong Jiaxing Zu Yuqin Xin Ke Huang Quan Zhou Yaojie Liu Lin Zhou Li Wang Yang Liu Ge Zhang Southwest Branch of State Grid Corporation of China Chengdu 610094China Lhasa Plateau Ecosystem Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100090China Xizang Xinhe Supervision and Consulting Limited Company Lhasa 850000China International Institute for Earth System Science Nanjing UniversityNanjing 210023China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Peking University Shenzhen Graduate School Shenzhen 518055China State Grid Sichuan Electric Power Company Chengdu 610094China School of Urban and Environment Liaoning Normal UniversityDalian 116029China Heilongjiang University of Science and Technology Harbin 150001China

Aims Vegetation dynamics are simultaneously regulated by climate change and anthropogenic *** the 1980s,climate has been warming on the Tibetan Plateau(TP)at a rate higher than North Hemisphere *** activities,including grazing,farming,and urbanization,are also influencing the alpine ecosystem on the ***,an ensemble of large engineering projects,such as power transported from west to east by State Grid,has been in operation on the *** studies disentangling effects of climate and anthropogenic activities interference are still lacking for the forest ecosystems on the *** overarching objectives of this study were to separate effects of natural climates and human interferences on forest ecosystem dynamics on the *** We compared vegetation activities of two typical natural reserves(Gongbu natural reserve,GNR,and Yarlung zangbo river grand canyon natural reserve,YNR)and their surroundings in southeastern Tibet(outside of the natural reserves,ONR)using long-term satel-lite normalized difference vegetation index(NDVI)*** regression and partial correlation analyses were constructed for the relationship between vegetation activity and climates to evaluate the distinct climate effects on the two natural *** Findings The two natural reserves were established at different time,which were related to anthropogenic activities impact *** results showed that the annual mean NDVI fluctuated between 0.5 and 0.6 in the relatively longer reserved YNR,which was re-markably higher than those in other regions(with NDVI lower than 0.45).The vegetation vigor in the YNR showed neither a sig-nificant temporal trend nor significant relationship with ***,vegetation vigor exhibited a significant increasing trend during the last three decades(0.012/decade)at the *** inter-decadal analysis turned out positive relationships between vegetation vigor and annual temperature since late 1990s u

关键词： climate change human interference natural reserves vegetation activity Southeastern Tibet

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Corrigendum to "Environmental impact of adult incontinence products in China in the context of population aging" [Sci. Total Environ. 875 (2023) 162596]

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The Science of the total environment 2023年 891卷 164571页

作者： Xinkai Gu Mingxing Sun Xinyi Long Huijing Deng Yutao Wang Fudan Tyndall Center Department of Environmental Science & Engineering Fudan University Shanghai 200438 China. Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China. Fudan Tyndall Center Department of Environmental Science & Engineering Fudan University Shanghai 200438 China Institute of Eco-Chongming (IEC) No.3663 Northern Zhongshan Road Shanghai 200062 China IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather Shanghai China Shanghai Institute for Energy and Carbon Neutrality Strategy Fudan University Shanghai China. Electronic address: yutaowang@***.

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Analyzing the velocity of urban dynamic over northeastern China using DMSP-OLS night-time lights

Analyzing the velocity of urban dynamic over northeastern Ch...

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ISPRS Geospatial Week 2017

作者： Zhou, Yuke Key Laboratory of Ecosystem Network Observation and Modeling IGSNRR CAS Beijing China

Stable night-time lights (NTL) data from the Defense Meteorological Satellite Program Operational Line-scan System (DMSP-OLS) can serve as a good proxy for anthropogenic development. Here DMSP-OLS NTL data was used to detect the urban development status in northeastern China. The spatial and temporal gradients are combined to depict the velocity of urban expanding process. This velocity index represents the instantaneous local velocity along the Earth's surface needed to maintain constant NTL condition, and has a mean of 0.36km/yr for northeastern China. The velocity change of NTL is lower in the urban center and its near regions, and the suburbs show a relatively high value. The connecting zones between satellite cities and metropolis have also a rapid rate of NTL evolution. The dynamic process of urbanization over the study area is mainly in a manner of spreading from urban cores to edges. The rank size of the velocity for the prefectures is analyzed and a long tail distribution is found. The velocity index can provide insights for the future pattern of urban sprawl. © Authors 2017. CC BY 4.0 License.

关键词： Velocity

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N concentration of old leaves and twigs is more sensitive to stand density than that of young ones in Chinese fir plantations： a case study in subtropical China

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Journal of Forestry Research 2018年第1期29卷 163-169页

作者： Yuebao Di Xiaoli Fu Huimin Wang Wenhua Li Silong Wang Qianyanzhou Ecological Research Station Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 People's Republic of China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190 People's Republic of China Jiangxi Key Laboratory of Ecosystem Processes and Information Ji'an 343725 People's Republic of China Huitong Experimental Station of Forest Ecology Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of Sciences Sbenyang 110016 People' s Republic of China

Young leaves are conventionally used in the analysis to study the nutrient status of evergreen plants and their responses to environmental changes, but the role of old leaves remains poorly understood. We selected two stand types in 31-year-old Chinese fir（Cunninghamia lanceolata） plantations with similar soil conditions but different stand densities, to test the hypothesis that nitrogen（N） concentration of old leaves and twigs is more sensitive to stand density than that of young ones. Leaves and twigs were sampled and sorted into young（one-year-old） and old（two-and three-year-old） groups. Significant differences in N concentration and carbon： nitrogen ratio between the low-density stand and high-density stand were only found in the old leaves and twigs but not in the young *** the N resorption efficiency did not vary significantly with stand density, the annual N resorption rates were increased in old leaves and relatively young twigs at high stand density. These results show the potential use of old tissues in the nutrient analysis in Chinese fir plantations. Testing the generality of these results could improve the use of foliar analysis as an indicator of nutrient status and environmental changes in evergreen tree species.

关键词： Foliar analysis Twig Nitrogen Nutrient resorption Stand density

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Chinese Cropland Quality and Its Temporal and Spatial Changes due to Urbanization in 2000–2015

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Journal of Resources and Ecology 2019年第2期10卷 174-183页

作者： WANG Chunyu SUN Xiaofang WANG Meng WANG Junbang DING Qingfu College of Geography and Tourism Qufu Nonnal University Rizhao Shandong 276826 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Shangdong Provincial Institute of Land Surveying and Mapping Jinan 250013 China

The acceleration of urbanization has led to the occupation of more cropland, especially higher quality cropland, which could pose a huge threat to food security and have other implications for the inadequate cropland resource supply in China. Though the spatial status of Chinese cropland quality has been assessed, its temporal changes since 2000 to 2015 are still not clear. An accumulated probability distribution method was used to determine the criteria of cropland quality using the net primary production data product(MOD17) from Moderate Resolution Imaging Spectroradiometer(MODIS). Then the cropland quality of higher, median and lower production was spatially mapped and its changes due to occupation by urbanization were analyzed through the land use changes(LUCC) data primarily from Landsat TM images in the three periods of 2000–2005, 2005–2010, and 2010–*** results showed that of the total cropland reduction area the proportion taken by urbanization increased from47.29% in the early stage to 77.46% in the recent period. The quality of Chinese cropland was dominated by lowand medium-yield fields, accounting for 40.81% and 48.74%, respectively, with high-yield fields accounting for only 10.44% of the total cropland in the country in 2000. The high-yield areas have been seriously threatened by the expansion of construction land fields, with the ratio of high-yield area to total area occupied by urbanization increasing from 9.71% in 2000–2005 to 15.63% in 2010–2015. Spatially, this phenomenon has been moving from eastern and southern China to central and western China, especially in Northwest China where the ratio has arrived at the highest proportion, with 52.97% of high-yield cropland in the total land taken by the expansion by 2015. This study not only provides a method to assess cropland quality but also reveals the threatening trend from the expansion of urbanization on high-quality cropland. More attention should be paid to the latter in land use planning

关键词： cropland quality cropland quantity urbanization spatial-temporal changes remote sensing

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