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stable isotope Signatures and Moisture Transport of a Typical Heavy Precipitation Case in the Southern Tianshan Mountains

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Chinese Geographical Science 2020年第1期30卷 180-188页

作者： WANG Liwei ZHANG Mingjun WANG Shengjie Athanassios AARGIRIOU WANG Gaofei Vasileios SALAMALIKIS SHI Mengyu JIAO Rong College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China Institute of Desert Meteorology China Meteorological AdministrationUrumqi 830002China State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Laboratory of Atmospheric Physics Physics DepartmentUniversity of PatrasPatras G&26500Greece Meteorological Bureau of Jeminay County Xinjiang Altay 836500China

stable oxygen isotopes in precipitation contain meaningful environmental information on a synoptic scale and can be applied to diagnose hydrometeorological processes.A series of rainstorms occurred at the southern Tianshan Mountains during the period from May to June 2013,and the event-based precipitation was sampled along the mountain range from west to east.Based on δ18 O values in precipitation samples as well as the corresponding meteorological parameters,the moisture transport paths during the sampling period were identified.In late-May(stage 1),isotopes in precipitation collected generally showed a depleting trend.In mid-June(stage 2),there was no coherent trend of isotopes in precipitation for these stations,and only isotope values in Aksu showed a continually depleting trend.Checking other meteorological proxies during the sampling period,the event-based precipitation isotopes sensitively reflected the moisture process.In central Asia,both the westerly and monsoon moisture can be delivered to cause extreme precipitation events,and the isotopic information provides an alternative tool to investigate the atmospheric processes.

关键词： precipitation stable isotope moisture source Tianshan Mountains

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Dietary preferences and potential ecological impact on the zooplankton community of Nemopilema nomurai based on stable isotope and fatty acid analyses

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Journal of Oceanology and Limnology 2022年第3期40卷 1085-1096页

作者： Junjian WANG Chaolun LI Guang YANG Zhencheng TAO Yanqing WANG Haochen XIAN Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China North China Sea Marine Forecasting Center of State Oceanic Administration Qingdao 266100China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China Department of Engineering and Technology Institute of Oceanology Chinese Academy of SciencesQingdao 266071China

Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model stable isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.

关键词： Nemopilema nomurai fatty acid stable isotope dietary preferences

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Inferring trophic variation for Antarctic krill(Euphausia superba) in the Antarctic Peninsula from the austral fall to early winter using stable isotope analysis

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Acta Oceanologica Sinica 2018年第6期37卷 90-95页

作者： ZHU Guoping ZHANG Haiting SONG Qi YANG Yang WANG Shaoqin YANG Qingyuan College of Marine Sciences Shanghai Ocean University Shanghai 201306 China National Engineering Research Center for Oceanic Fisheries Shanghai 201306 China Polar Marine Ecosystem Group Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources Shanghai Ocean University Ministry of Education Shanghai 201306 China

The Antarctic krill（Euphausia superba） is a key species in the Southern Ocean ecosystem and an important link in the food web of the Antarctic ecosystem. The trophic information for this species during the transition from the austral fall to the winter is important to understand its poorly known overwintering mechanisms. However, the few studies on the topic differ in their results, in terms of both spatial and temporal variables. We investigated the size dependence and monthly and regional variation in δ^（13） C and δ^（15） N values of adult krill in the Antarctic Peninsula, in the austral fall（April to May） and the early winter（June）. We aimed to examine the trophic variations of krill occurred during this period, and the relationship between krill and their feeding environment in the Antarctic marine ecosystem. The following results were obtained：（1） no significant relationship was observed between size and the δ13 C value of krill, but the δ15 N value of krill presented a remarkable association with size;（2）the δ13 C values of krill increased during the austral fall, but no remarkable variation existed at the onset of winter,and the δ15 N values were not significant different during this period;（3） mean δ15 N values of krill differed significantly between the Bransfield Strait and the South Shetland Islands. Our data imply that adult krill present size-, season-, and region-dependent trophic variation during the transition from austral fall to early winter in the Antarctic Peninsula.

关键词： Euphausia superba stable isotope trophic variation Antarctic Peninsula feeding habit

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Spatial variations in food web structures with alternative stable states:evidence from stable isotope analysis in a large eutrophic lake

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Journal of Oceanology and Limnology 2018年第2期36卷 385-394页

作者：李云凯张毓颖徐军张硕 College of Marine Sciences Shanghai Ocean University Marine Sciences Program School of Environment Arts and Society Florida International University Donghu Experimental Station of Lake Ecosystems State Key Laboratory of Freshwater Ecology and Biotechnology of China Institute of Hydrobiology Chinese Academy of Sciences

Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in dif ferent trophic pathways. stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic dif ferences between basins with dif ferent environmental characteristics. Such differences likely result from isotopic baseline dif ferences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

关键词： stable isotope food web structure spatial heterogeneity Taihu Lake community

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Application of enriched stable isotope technique to the study of copper bioavailability in Daphnia magna

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Journal of Environmental Sciences 2011年第5期23卷 831-836页

作者： Wenhong Fan Chenguang WU Chunmei Zhao Tao Yu Yuan Zhang Department of Environmental Science and Engineering School of Chemistry and Environment Beihang University Beijing 100191 China. E-mail: fanwh @ buaa. edu. cn Chinese Research Academy of Environmental Sciences Beijing 100012 China

The biokinetics of Cu in Daphnia magna, including dissolved uptake, assimilation and efflux, has been determined using a gamma 67^Cu radiotracer methodology. However, this gamma emitting radioisotope is not readily available due to its very short half-life. In the present study, we employed a stable isotope tracer （65^Cu） to determine the Cu biokinetics and compared our results to those determined using 67^Cu. The dissolved uptake rate constant of 65^Cu was 3.36 L/（g.day）, which is higher than that of 67^Cu （1.32 L/（g.day））. With increasing food concentrations from 2×10^4 to 1×10^5 cells/mL, the Cu assimilation efficiency （AE） decreased from 46% to 11%, compared to a decrease from 27% to 16% when determined using 67^Cu. The effiux of Cu from Daphnia magna was quantified following both dissolved and dietary uptake. The efflux of waterborne Cu was comparable to that of dietborne Cu and the effiux rate constant （0.32-0.52 day^-l） was higher than that determined by 67^Cu （0.19-0.20 day^-1）. By considering different water properties and handling procedure between the two experiments, we believe that these differences are reasonable. Overall, this study demonstrated that the enriched stable isotope tracer technique is a powerful tool to investigate metal bioavailability and maybe a good alternative to radioactive measurements.

关键词： stable isotope Daphnia magna copper bioavailability

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Cleaning of Marine Sediment Samples for Large Diatom stable isotope Analysis

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Journal of Earth Science 2012年第2期23卷 161-172页

作者：熊志方李铁刚 Xavier Crosta Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of Sciences UMR-CNRS 5805 EPOC UniversitéBordeaux 1Avenue des Facultés

Diatom stable isotope analysis offers considerable potential in palaeoceanography, par-ticularly where carbonate material is scarce or absent. However, extracting pure diatom frustules free of external labile organic matter from marine sediments is an essential requirement for their applica-tions as paleoenvironmental proxies. Here, based largely on previous work, we developed a method in-cluding physical separation and chemical oxidation steps to concentrate and clean pure large diatoms from laminated diatom mat and diatomaceous clay sediment samples for their stable isotope analysis. Using the physical separation techniques consisting of the removal of carbonate and excess organic matter, sieving, differential settling, and heavy liquid floatation, pure diatoms can be successfully iso-lated from the sediment samples with opal concentration more than 10%. Subsequent time oxidation experiment shows that labile organic matter coating pure diatom valves can be effectively removed with 30% H2O2 at 65 ℃ for 2 h. Measurements of δ13C after every step of physical separation demonstrate that contaminants and lost diatoms can influence the original diatom stable isotope signal, highlighting the importance of a visual check for dominant diatom size in the initial sample and purity in the final sample. Although the protocol described here was only applied to diatom mats or diatom oozes con-taining large diatoms （Ethmodiscus rex）, we believe that this method can be adapted to common dia-toms of general marine sediment samples.

关键词： large diatom stable isotope physical separation chemical oxidation Parece Vela basin palaeoceanography.

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stable isotope in precipitation in China:A review

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Research in Cold and Arid Regions 2012年第1期4卷 83-90页

作者： YaJu Li MingJun Zhang ShengJie Wang ZhongQin Li FeiTeng Wang College of Geography and Environment Sciences Northwest Normal University Lanzhou Gansu 730070 China State Key Laboratory of Cryospheric Seiences/Tianshan Glaciological Station Cold and Arid Regions Environmental and En- gineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China

The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric processes, tracing vapor sources, and reflect- ing the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during the past several decades is presented and the prospects for future work in this subject area are described.

关键词： precipitation stable isotope spatio-temporal distribution China

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Application of stable isotope techniques to the study of soil salinization

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Journal of Arid Land 2011年第4期3卷 285-291页

作者： YongQin CUI JianYing MA Wei SUN Dunhuang Gobi and Desert Ecology and Environment Research Station Cold and Arid Regions Environmental and Engineering Research Institute CAS Lanzhou 730000 China Key Laboratory of Vegetation Ecology Ministry of Education Institute of Grassland Sciences Northeast Normal University Changchun 130024 China

In this paper, we reviewed the progress in the application of stable isotope techniques to the study of soil salinization. As a powerful technique, stable isotopes have been widely used in the studies of soil water evaporation, the dynamics of soil salinization and salt-tolerant plant breeding. The impact of single environmental factors on plant isotope composition has been the focus of previous studies. However, the impact of multiple envi- ronmental factors on plant isotope composition remains unclear and needs to be carefully studied. In order to gain insights into soil salinization and amelioration, especially soil salinization in arid and semiarid areas, it is essential to employ stable isotope techniques and combine them with other methods, such as located field observation and remote sensing technology.

关键词： stable isotope soil water evaporation soil salinization dynamic salt-tolerant plants breeding

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Preparation of stable isotope Standard Samples of Carbon and Nitrogen in Beef Protein

Preparation of Stable Isotope Standard Samples of Carbon and...

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2018年中国质谱学术大会（CMSC2018）

作者： Zhao Yan Zhao Shanshan Qie Mengjie Institute of Quality Standard and Testing Technology for Agro-Products Chinese Academy of Agricultural Sciences

isotope standard samples are essential to enable reliable isotope data. From the beginning of isotopic measurements, there are isotope standard samples. It continues to evolve with the development of isotope research. In this study, two beef proteins have been prepared as standard samples for C and N abundances measurements. First, two kinds of beef samples were collected, followed by diced, ground and freeze-dried for 24 h. Then, the beef samples was extracted with petroleum ether for 6 h in a Soxhlet apparatus. The defatted dry mass of beef was ground in a mortar to pass a 100-mesh sieve. The sieved samples were collected in a trough type mixer and tumbled for 2 h, then was dried in an oven at 50℃ for 4 h to obtain standard samples. The standard samples were sterilized by irradiation and tested for moisture homogeneity and stability tests. The δC and δN values of international reference materials USGS42、USGS43 were measured against the two beef standard samples and common glutamic acid standard samples by stable isotope-ratio mass spectrometry, respectively. It was found that the calibration data of the beef standard sample compared to the common glutamic acid standard sample is closer to the given value of USGS42 and USGS43.

关键词： stable isotope standard sample beef protein

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Fractionation mechanism of stable isotope in evaporating water body

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Journal of Geographical Sciences 2005年第3期15卷 375-384页

作者： ZHANG Xinping TIAN Lide LIU Jingmiao College of Resources and Environmental Sciences Hunan Normal University Changsha 410081 China Cold and Arid Regions Environmental and Engineering Research Institute CAS Lanzhou 730000 China Chinese Academy of Meteorological Sciences Beijing 100091China

Under Rayleigh equilibrium condition, stable isotopic ratio in residual water increases with the decrease of the residual water proportion f exponentially, and the fractionation rate of stable isotopes is inversely proportional to temperature. However, under kinetic evaporation condition, the fi＇actionation of stable isotopes is not only related to the phase temperature but also influenced by the atmospheric humidity and the mass exchange between liquid and vapor phases. The ratio 6 in residual water will not change with f after undergoing evaporation of a long time for great relative humidity. The rate that the evaporating water body reaches isotopic steady state is mainly dependent on the relative humidity in atmosphere. The analysis shows that the actual mean linear variety rates, about -30.0, of the δ^18O in residual water versus the residual water proportion at Nagqu and Amdo stations are consistent with the simulated process under temperature of 20℃ and relative humidity of 50%. The distillation line simulated under Rayleigh equilibrium condition is analogous to the global meteoric water line （MWL） as the temperature is about 20℃. Under non-equilibrium condition, the slope and constant values of distillation line are directly proportional to temperature and relative humidity. According to the basic data, the simulated distillation line is very consistent with the actual distillation line of Qinghai Lake.

关键词： stable isotope evaporation kinetic fractionation distillation line water body

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