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Patterns of Soil ^(15)N and Total N and Their Relationships with Environmental Factors on the Qinghai-Tibetan Plateau

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Pedosphere 2014年第2期24卷 232-242页

作者： ZHOU Lei SONG Ming-Hua WANG Shao-Qiang FAN Jiang-Wen LIU Ji-Yuan ZHONG Hua-Ping YU Gui-Rui GAO Lu-Peng HU Zhong-Min CHEN Bin WU Wei-Xing SONG Ting Key Laboratory of ecosystem network Observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of chinese Academy of Sciences

The patterns of soil nitrogen （N） isotope composition at large spatial and temporal scales and their relationships to environmental factors illustrate N cycle and sources of N, and are integrative indicators of the terrestrial N cycle and its response to global change. The objectives of this study were： i） to investigate the patterns of soil N content and natural abundance of 15N （δ15N） values in different ecosystem types and soil profiles on the Qinghai-Tibetan Plateau; ii） to examine the effects of climatic factors and soil characteristics on the patterns of soil N content and soil δ15N values; and iii） to test the relationship between soil δ15N values and soil C/N ratios across ecosystems and soil profiles. Soil profiles were sampled at 51 sites along two transects 1 875 km in length and 200 km apart and distributed in forest, meadow and steppe on the Qinghai-Tibetan Plateau. Each site was sampled every 10 cm from a soil depth of 0 to 40 cm and each sample was analyzed for soil N content and δ15N values. Our results indicated that soil N and 515N values （0-40 cm） in meadows were much higher than in desert steppe. Soil N decreased with soil depth for each ecosystem, while variations of soil ~15N values along soil profiles were not statistically significant among most ecosystems but for mountain meadow, lowland meadow, and temperate steppe where soil δ15N values tended to increase with soil depth. The parabolic relationship between soil δ15N values and mean annual precipitation indicated that soil δ15N values increased with increasing precipitation in desert steppe up to 500 mm, and then decreased with increasing precipitation across all other ecosystems. Moreover, the parabolic relationship between δ15N values and mean annual temperature existed in all individual ecosystem types. Soil N and δ15N values （0-0 cm） increased with an increase in soil silt and clay contents. Furthermore, a threshold of C/N ratio of about 11 divided the parabolic relationship between soi

关键词： desert steppe nitrogen isotope composition nutrient availability soil nitrogen

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Spatial pattern of grassland aboveground biomass and its environmental controls in the Eurasian steppe

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Journal of Geographical Sciences 2017年第1期27卷 3-22页

作者： JIAO Cuicui YU Guirui HE Nianpeng MA Anna GE Jianping HU Zhongmin Synthesis research Center of chinese ecosystem research network Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of chinese Academy of Sciences Beijing 100049China College of Life Sciences Beijing Normal UniversityBeijing 100875China

Vegetation biomass is an important component of terrestrial ecosystem carbon stocks. Grasslands are one of the most widespread biomes worldwideplaying an important role in global carbon cycling. Thereforestudying spatial patterns of biomass and their correlations to environment in grasslands is fundamental to quantifying terrestrial carbon budgets. The Eurasian steppean important part of global grasslandsis the largest and relatively well preserved grassland in the world. In this studywe analyzed the spatial pattern of aboveground biomass（AGB）and correlations of AGB to its environment in the Eurasian steppe by meta-analysis. AGB data used in this study were derived from the harvesting method and were obtained from three data sources（literatureglobal NPP database at the Oak Ridge National Laboratory Distributed Active Archive Center（ORNL）some data provided by other researchers）. Our results demonstrated that：（1） as for the Eurasian steppe overallthe spatial variation in AGB exhibited significant horizontal and vertical zonality. In detailAGB showed an inverted parabola curve with the latitude and with the elevationwhile a parabola curve with the longitude. In additionthe spatial pattern of AGB had marked horizontal zonality in the Black Sea-Kazakhstan steppe subregion and the Mongolian Plateau steppe subregionwhile horizontal and vertical zonality in the Tibetan Plateau alpine steppe subregion.（2） Of the examined environmental variablesthe spatial variation of AGB was related to mean annual precipitation（MAP）mean annual temperature（MAT）mean annual solar radiation（MAR）soil Gravel contentsoil p H and soil organic content（SOC） at the depth of 0–30 cm. NeverthelessMAP dominated spatial patterns of AGB in the Eurasian steppe and its three subregions.（3） A Gaussian function was found between AGB and MAP in the Eurasian steppe overallwhich was primarily determined by unique patterns of grasslands and environment in the Tibetan Plateau. AGB was significantly positively relat

关键词： the Eurasian steppe aboveground biomass spatial pattern parabola curve Gaussian function

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Prediction of carbon exchanges between China terrestrial ecosystem and atmosphere in 21st century

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Science China Earth Sciences 2008年第6期51卷 885-898页

作者： JI JinJun HUANG Mei LI KeRang chinese ecosystem research network Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.

关键词： carbon cycle AVIM2 climate change B2 scenario China terrestrial ecosystems

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Responses of greenhouse gas fluxes to experimental warming in wheat season under conventional tillage and no-tillage fields

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Journal of Environmental Sciences 2017年第4期29卷 314-327页

作者： Chun Tu Fadong Li Key Laboratory of ecosystem network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

Understanding the effects of warming on greenhouse gas（GHG, such as N2O, CH4 and CO2 ）feedbacks to climate change represents the major environmental issue. However, little information is available on how warming effects on GHG fluxes in farmland of North China Plain（NCP）. An infrared warming simulation experiment was used to assess the responses of N2O, CH4 and CO2 to warming in wheat season of 2012–2014 from conventional tillage（CT） and no-tillage（NT） systems. The results showed that warming increased cumulative N2O emission by 7.7% in CT but decreased it by 9.7% in NT fields（p 〈 0.05）. Cumulative CH4 uptake and CO2 emission were increased by 28.7%–51.7% and 6.3%–15.9% in both two tillage systems,respectively（p 〈 0.05）. The stepwise regressions relationship between GHG fluxes and soil temperature and soil moisture indicated that the supply soil moisture due to irrigation and precipitation would enhance the positive warming effects on GHG fluxes in two wheat ***, in 2013, the long-term drought stress due to infrared warming and less precipitation decreased N2O and CO2 emission in warmed treatments. In contrast, warming during this time increased CH4 emission from deep soil depth. Across two years wheat seasons, warming significantly decreased by 30.3% and 63.9% sustained-flux global warming potential（SGWP） of N2O and CH4 expressed as CO2 equivalent in CT and NT fields, respectively. However, increase in soil CO2 emission indicated that future warming projection might provide positive feedback between soil C release and global warming in NCP.

关键词： Climate warming Greenhouse gas fluxes(N2O CH4 CO2) Conventional tillage No-tillage Soil temperature Soil moisture

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Rapid recovery of desert shrubs is attributed to imbalance of water supply to demand after disturbance in Northwest China

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Ecological Processes 2024年第2期13卷 118-129页

作者： Hai Zhou Xiangyan Feng Zhibin He Qiyue Yang Heng Ren Wenzhi Zhao Linze Inland River Basin research Station Chinese Ecosystem Research Network Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences University of chinese Academy of Sciences

Background Disturbance is a key driver of changes in terrestrial ecosystems, especially in water limited regions. In the desert ecosystem of Northwest China, shrubs are often foraged by camels and this causes the shrubs lost their aboveground tissues. Although the aboveground tissue could recover after the disturbance, the mechanisms of resprouts' recovery after the disturbance are still poorly understood. We investigated the morphological and physiological characteristics and root water uptake sources of resprouts and non-disturbed seedlings of four desert shrub species that were often foraged by *** The results showed that the resprouts grew rapidly after the removal of aboveground tissue. The height and aboveground biomass of resprouts reached the level of 5-year-old seedlings following a growing season. Compared to un-disturbed seedlings, higher leaf water potential, leaf hydraulic conductance and photosynthesis rate were observed in resprouts, indicating that resprouts grew rapidly after disturbance. Furthermore, we found that the root water uptake source did not change after disturbance. This indicated that the roots of resprouts kept intact water uptake capacity after disturbance, which could keep supplying sufficient water to the aboveground tissue. Due to the removal of aboveground tissue of the resprouts, the water demand of aboveground tissue decreased, which induced an imbalance of water supply from roots to demand of aboveground tissues of resprouts. This explained the improved physiological performance and rapid recovery of resprouts after *** The imbalance of water supply to demand contributes to the rapid recovery of desert shrubs after disturbance. The findings provide insight into the eco-physiological mechanism for the maintenance of desert ecosystems that are facing disturbance.

关键词： Disturbance Resprout Physiological performance Shrub Water uptake source

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Biomass Allocation Patterns of Alpine Grassland Species and Functional Groups along a Precipitation Gradient on the Northern Tibetan Plateau

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Journal of Mountain Science 2013年第6期10卷 1097-1108页

作者： WU Jian-shuang SHEN Zhen-xi ZHANG Xian-zhou SHI Pei-li Lhasa National Ecological research Station Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of sciences

Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups： forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation （MAP） gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes.

关键词： Biomass fractions Complementaryresponse Functional components Functional groups Changtang Plateau

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Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China,2004-2010

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Journal of Environmental Sciences 2013年第5期25卷 1007-1014页

作者： Xinyu Zhang Zhiwei Xu Xiaomin Sun Wenyi Dong Deborah Ballantine Key Laboratory of ecosystem network Observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences National Institute of Water and Atmospheric research HamiltonNew Zealand

The nitrate-nitrogen（NO 3-N） concentrations from shallow groundwater wells situated in 29 of the chinese ecosystem research network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and *** from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be *** indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the chinese National Standard：Quality Standard for Ground Water（≤ 20 mg/L）.Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems（4.1 ± 0.33 mg/L） than in forest ecosystems（0.5 ± 0.04 mg/L）.NO 3-N concentrations were relatively higher（〉 10 mg N /L） in 10 of the 43 wells sampled in the agricultural *** elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are *** suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.

关键词： chinese ecosystem research network shallow groundwater agricultural forest ecosystems nitrate concentration

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Evapotranspiration of an oasis-desert transition zone in the middle stream of Heihe River, Northwest China

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Journal of Arid Land 2014年第5期6卷 529-539页

作者： LiWen ZHAO WenZhi ZHAO Linze Inland River Basin research Station Chinese Ecosystem Network Research Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe

关键词： evapotranspiration pan evaporation water requirement arid region oasis-desert transition zone

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Effects of Grazing Exclusion on Plant Productivity and Soil Carbon, Nitrogen Storage in Alpine Meadows in Northern Tibet, China

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chinese Geographical Science 2014年第4期24卷 488-498页

作者： XIONG Dingpeng SHI Peili SUN Yinliang WU Jianshuang ZHANG Xianzhou Lhasa National Ecological research Station Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of chinese Academy of Sciences

Grazing exclusion is widely adopted in restoring degraded alpine grasslands on the Qinghai-Tibetan Plateau. However, its effectiveness remains poorly understood. In this study, we investigated the effects of grazing exclusion on plant productivity, species diversity and soil organic carbon （SOC） and soil total nitrogen （STN） storage along a transect spanning from east to west of alpine meadows in northern Tibet, China. After six years of grazing exclusion, plant cover, aboveground biomass （AGB）, belowground biomass （BGB）, SOC and STN were increased, but species diversity indices declined. The enhancement of AGB and SOC caused by grazing exclusion was correlated positively with mean annual precipitation （MAP）. Grazing exclusion led to remarkable biomass increase of sedge species, especially Kobresia pygmaea, whereas decrease of biomass in forbs and no obvious change in grass, leguminous and noxious species. Root biomass was concentrated in the near surface layer （10 cm） after grazing exclusion. The effects of grazing exclusion on SOC storage were confined to shallow soil layer in sites with lower MAP. It is indicated that grazing exclusion is an effective measure to increase forage production and enhance soil carbon sequestration in the studied region. The effect is more efficient in sites with higher precipitation. However, the results revealed a tradeoff between vegetation restoration and ecological biodiversity. Therefore, carbon pools recover more quickly than plant biodiversity in the alpine meadows. We suggest that grazing exclusion should be combined with other measures to reconcile grassland restoration and biodiversitv conservation.

关键词： aboveground biomass belowground biomass soil organic carbon (SOC) soil total nitrogen (STN) biodiversity grazingexclusion precipitation alpine meadow

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Lipids and fatty acids in Calanus sinicus during over-summering in the southern Yellow Sea

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chinese Journal of Oceanology and Limnology 2017年第4期35卷 874-882页

作者：王延清李超伦刘梦坛金鑫 Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of Sciences University of chinese Academy of Sciences Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and Technology Jiaozhou Bay Marine ecosystem research Station Chinese Ecosystem Research Network

Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton *** play an important role in copepod diapause,which is part of their over-summering *** investigated how different fatty acids and lipid classes,including wax esters,changed during over-summering of *** during three cruises in June and August 2011 and November 2010,corresponding to the pre-,during and post-diapause periods,*** amounts of lipids were accumulated,mainly wax esters as previously found in *** during its diapause,and most of the storage lipids were used during *** ester polyunsaturated fatty acids(PUFAs) showed the most variation of the fatty acids(FAs),while the percentage composition of FAs in polar lipids was relatively *** use of wax ester PUFAs has already been shown to play important roles in the winter diapause of Calanus species in other regions,and our FA results show that this is the case for the Yellow Sea Cold Bottom Water(YSCBW) population that diapauses in summer.

关键词： Calanus sinicus lipid wax ester polar lipid polyunsaturated fatty acids (PUFAs)

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