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Effects of Water Vapor Source and Local Evaporation on the Stable Hydrogen and Oxygen Isotopic Compositions of Precipitation

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Huanjing Kexue/Environmental Science 2019年第2期40卷 573-581页

作者： Hu, Yong-Bo Xiao, Wei Qian, Yu-Fei Liu, Qiang Xie, Cheng-Yu Zhang, Xiu-Fang Zhang, Wen-Qing Wen, Xue-Fa Liu, Shou-Dong Lee, Xu-Hui Yale-NUIST Center on Atmospheric Environment Nanjing University of Information Science and Technology Nanjing210044 China Nanjing University of Information Science and Technology Nanjing210044 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China

Stable hydrogen and oxygen isotopic compositions in precipitation are good tracers and can provide unique information about the water cycle. Precipitation samples were collected at the Nanjing, Liyang, Yixing, and Dongshan sites in 2016, and the HDO and H218O compositions of precipitation were measured. The temporal variability of HDO and H218O compositions and deuterium-excess of precipitation were analyzed, and the influence of the water vapor source and local evaporation on stable isotopic composition of precipitation were discussed. The results indicated that: ① Seasonal variations in the HDO composition, H218O composition, and deuterium-excess of precipitation occurred due to different water vapor sources during the summer and winter monsoon seasons. The HDO and H218O compositions were depleted during the summer monsoon season and enriched during the winter monsoon season. The deuterium-excess during the summer monsoon season was lower compared to the winter monsoon season. ② During the summer monsoon, the evaporation of Lake Taihu made the deuterium-excess of downwind precipitation and the downwind intercept of the local meteoric water line higher. During the winter monsoon season, local evaporation had little influence on HDO and H218O components in precipitation. ③ Both of the intercepts and slopes of the local meteoric water line were higher than those of the global meteoric water line, due to moisture recycling during the winter monsoon season and different water vapor sources between the summer and winter monsoon seasons. © 2019, Science Press. All right reserved.

关键词： Oxygen

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Soil erosion affects variations of soil organic carbon and soil respiration along a slope in Northeast China

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Ecological Processes 2019年第1期8卷 360-369页

作者： Tong Li Haicheng Zhang Xiaoyuan Wang Shulan Cheng Huajun Fang Gang Liu Wenping Yuan State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Le Laboratoire des Sciences du Climat et de l’Environnement IPSL-LSCECEA/CNRS/UVSQ SaclayGif-sur-YvetteFrance College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Guangdong Province Key Laboratory for Climate Change and Natural disaster Studies School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519082China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai 519082China

Background:Although soil erosion plays a key role in the carbon cycle,a holistic and mechanistic understanding of the soil erosion process within the cycle is still *** aim of this study was therefore to improve our mechanistic understanding of soil organic carbon(SOC)and soil respiration dynamics through an experiment conducted in an eroding black soil farmland landscape in Northeast ***:The depositional profiles store 5.9 times more SOC than the eroding profiles and 3.3 times more SOC than the non-eroding profiles.A linear correlation between the SOC and 137Cs(Caesium-137)was observed in our study,suggesting that the SOC decreased with increased soil ***,the fractions of intermediate C and the microaggregate C were lowest at the eroding position and highest at the depositional *** the depositional topsoil,the input of labile materials plays a promotional role in soil ***,in the subsoil(i.e.,below 10 cm),the potential mineralization rates were lowest at the depositional position—due to effective stabilization by physical protection within soil *** field results of soil surface respiration also suggest that the depositional topsoil SOC is prone to be mineralized and that SOC at this depositional context is stabilized at subsoil *** addition,the high water contents at the depositional position can limit the decomposition rates and stabilize the SOC at the same ***:The findings from this study support that a majority of the SOC at footslope is stored within most of the soil profile(i.e.,below 10 cm)and submitted to long-term stabilization,and meanwhile support that the depositional profile emits more CO2 than the summit due to its high amount and quality of SOC.

关键词： Soil erosion Soil organic carbon Soil respiration Sloping farmland

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Spatial and Temporal Variations in Available Soil Nitrogen—A Case Study in Kobresia Alpine Meadow in the Qinghai-Tibetan Plateau, China

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Journal of Geoscience and Environment Protection 2019年第3期7卷 177-189页

作者： Li Lin Guangmin Cao Fawei Zhang Xun Ke Yikang Li Xingliang Xu Qian Li Xiaowei Guo Bo Fan Yangong Du Northwest Institute of Plateau Biology Chinese Academy of Science Xining China College of Life Science Luoyang Normal University Luoyang China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Elucidating the factors that determine the effects of temporal and spatial variation of nutrients is important for analyzing the characteristics of an ecosystem. The goal of this paper was to estimate how values obtained using a particular sampling approach correlated with the actual data for an entire plot. The mesh partition method was employed to divide an integrated observing field (IOF) located at the Haibei National Field Research Station of an alpine grassland ecosystem, China, into 25 subplots. Five of the 25 subplots were randomly selected for soil sampling and to determine the source of variations in soil nutrient content from 2001 to 2012. The results showed that, contributions of temporal and spatial variation in available nitrogen in the 0 - 10 cm soil layer accounted for 47.3% and 52.7%, respectively. The contribution of spatial variance was higher than that of temporal variance especially in the surface soil layers. The available soil nitrogen content in the alpine meadow was not obviously affected by fluctuations in rainfall and temperature. Increasing the number of samples could reduce calculation errors in measuring available soil nitrogen content, while collecting a reasonable number of samples can save time and labor.

关键词： Available Soil Nitrogen Source of Nutrient Variation Temporal Variation Spatial Variation Alpine Meadow

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A Functional Land Use Classification for Ecological, Production and Living Spaces in the Taihang Mountains

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Journal of Resources and Ecology 2019年第3期10卷 246-255页

作者： GENG Shoubao ZHU Wanrui SHI Peili Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100190 China

A combination of rapid industrialization, economic development and urbanization has caused a series of issues such as resource shortages, ecosystem destruction, environmental pollution and tension between human needs and land conservation. In order to promote balanced development of human, resources, ecosystems, the environment, and the economy and society, it is vital to conceptualize ecological spaces, production spaces and living spaces. Previous studies of ecological-production-living spaces focused mainly on urban and rural areas; few studies have examined mountainous areas. The Taihang Mountains, a key area between the North China Plain and Beijing-Tianjin-Hebei area providing ecological shelter and the safeguarding of crucial water sources, suffer from increasing problems of fragile environment, inappropriate land use and tensions in the human-land relationship. However, studies of the ecological, production, and living spaces in the Taihang Mountains are still lacking. Therefore, this study, based on the concept of ecological-production-living spaces and using data from multiple sources, took the Taihang Mountains as the study area to build a functional land classification system for ecological-production-living spaces. After the classification system was in place, spatial distribution maps for ecological, production and living spaces were delineated. This space mapping not only characterized the present land use situation, but also established a foundation for future land use optimization. Results showed that the area of ecological space was 78,440 km^2, production space 51,861 km^2 and living space 6,646 km^2, accounting for 57.28%, 37.87% and 4.85% of the total area, respectively. Ecological space takes up the most area and is composed mainly of forests and grasslands. Additionally, most of the ecological space is located in higher elevation mountainous areas, and plays an important role in regulating and maintaining ecological security. Production space,

关键词： ecological-production-living space la nd classificati on system la nd function spatial pattern the Taihang Mountains

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Accumulation of residual soil microbial carbon in Chinese fir plantation soils after nitrogen and phosphorus additions

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Journal of Forestry Research 2018年第4期29卷 948-957页

作者： Zhiqiang Ma Xinyu Zhang Chuang Zhang Huimin Wang Fusheng Chen Xiaoli Fu Xiangmin Fang Xiaomin Sun Qiuliang Lei Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research(CAS) College of Resources and Environment University of Chinese Academy of Sciences College of Land and Environment Shenyang Agricultural University College of Forestry Jiangxi Agricultural University Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences

Nitrogen （N） and phosphorus （P） additions can affect soil microbial carbon （C） accumulation. However, the mechanisms that drive the changes in residual microbial C that occur after N and P additions have not been well-defined for Chinese fir plantations in subtropical China. We set up six different treatments, viz. a control （CK）, two N treatments （NI： 50kgha-1 a-1; N2： 100 kg ha-1 a-1）, one P treatment （P： 50 kg ha-1 a-1）, and two combined N and P treatments （NIP： 50kgha-1a-1 of N ＋50kgha-1a-1 of P; N2P：100 kg ha-1 a-1 of N ＋ 50 kg ha-1 a-1 of P）. We then investigated the influences of N and P additions on residual microbial C. The results showed that soil pH and microbial biomass decreased after N additions, while microbial biomass increased after P additions. Soil organic carbon （SOC） and residual microbial C contents increased in the N and P treatments but not in the control. Residual microbial C accumulation varied according to treatment and declined in the order： N2P 〉 N1P 〉 N2 〉 N1 〉 P 〉 CK. Residual microbial C contents were positively correlated with available N, P, and SOC contents, but were negatively correlated with soil pH. The ratio of residual fungal C to residual bacterial C increased under P additions, but declined under combined N1P additions. The ratio of residual microbial C to SOC increased from 11 to 14% under the N1P and N2P treatments, respectively. Our results suggest that the concentrations of residual microbial C and the stability of SOC would increase under combined applications of N and P fertilizers in subtropical Chinese fir plantation soils.

关键词： Amino sugar Chinese fir plantation N and Padditions Residual microbial carbon Soil environmentvariable

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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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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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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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