Variation characteristics of stable isotopes in atmospheric precipitation in Adelaide,Australia

Background,aim,and scope Stable isotope in water could respond sensitively to the variation of environment and be reserved in different geological archives,although they are scarce in the environment.And the methods derived from the stable isotope composition of water have been widely applied in researches on hydrometeorology,weather diagnosis,and paleoclimate reconstruction,which help well for understanding the water-cycle processes in one region.Here,it is aimed to explore the temporal changes of stable isotopes in precipitation from Adelaide,Australia and determine the influencing factors at different timescales.Materials and methods Based on the isotopic data of daily precipitation over four years collected in Adelaide,Australia,the variation characteristics of dailyδD,δ^(18)O,and dexcess in precipitation and its relationship with meteorological elements were analyzed.Results The results demonstrated the local meteoric water line(LMWL)in Adelaide,wasδD=6.38×δ^(18)O+6.68,with a gradient less than 8.There is a significant negative correlation between dailyδ^(18)O and precipitation amount or relative humidity at daily timescales in both the whole year and wither/summerhalf year(p<0.001),but a significant positive correlation between dailyδ^(18)O and temperature in the whole year and the winter half-year(p<0.001).Discussion The correlation coefficients betweenδ^(18)O and daily mean temperature didn’t show a significant positive correlation,which may be attributed to that the precipitation in Adelaide area in January was mainly influenced by strong convective weather,and the stable isotope values in precipitation were significantly negative.Furthermore,this propose was also evidenced by the results from dexcess of precipitation with larger value in the winter half-year than that in the summer half-year,which may be resulted from the precipitation events in winter are mostly influenced by oceanic water vapor,while the sources of water vapor in summer precipitation events are more complicated and influenced by strong convective weather.On the other hand,the slope and intercept of theδ^(18)O—P regression lines in the summer months(-0.41 and 0.50‰)are larger and smaller than those in the winter months(-0.22 and-2.15‰),respectively,indicating that the precipitation stable isotopes have a relatively stronger rainout effect in the summer months than in the winter months.Besides,the measured values ofδ^(18)O in daily precipitation have a good linear relationship with our simulated values ofδ^(18)O,demonstrating the established regression model could provide a reliable simulation for theδ^(18)O values in daily precipitation in Adelaide area.It’s worth noting that the precipitation events with low precipitation amount,low relative humidity and high temperature,usually had relatively small slope and intercept of MWL,implying that raindrops may be strongly affected by sub-cloud secondary evaporation in the falling process.Conclusions The variation ofδ^(18)O in daily precipitation from Adelaide region was controlled by different factors at different timescales.And the water vapor sources and the meteorological conditions of precipitation events(such as the degree of sub-cloud secondary evaporation)also played an important role on the variation ofδ^(18)O.Recommendations and perspectives Stable isotope in daily precipitation can provide more accurate information about water-cycle and atmosphere circulation,it is therefore necessary to continue to collect and analyze daily-scale precipitation data over a longer time span.The results of this study will provide the basis for the fields of hydrometeorology,meteorological diagnosis and paleoclimate reconstruction in Adelaide,Australia.

Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

An accurate and sensitive method for the simultaneous determination of gibberellic acid（GA3）, gibberellin A4（GA4） and gibberellin A7（GA7） residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry（LC-MS/MS） with electrospray ionization based stable isotope dilution analysis（SIDA）. The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance（HLB） solid phase extraction（SPE） column was tested for the capacity of the cleanup of the tomato paste in compared with C18 SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA3, GA4 and GA7 were 42.6%―75.0% in external standard method（ESM） and 91.1%―103.8% in internal standard method（ISM） respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection（2 ng/g for GA3 and GA4, 0.3 ng/g for GA7）, excellent linear dynamic ranges（5―500 ng/g for GA3 and GA4, 1―100 ng/g for GA7） and good relative standard deviation ranges（4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test）.

Determination of trophic levels of marine fish in the Yellow Sea and northern East China Sea using nitrogen stable isotope (δ^(15)N) analysis of otoliths

Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.

UHAS-MIDA Software Package: Mass Isotopomer Distribution Analysis-Applying the Inverse Matrix for the Determination of Stable Isotopes of Chromium Distribution during Red Blood Cell Labelling

Clinical assessment of fluid volume status in children during malaria can be taxing and often inaccurate. During malaria, changes in fluid volume are rather multifarious and estimating this parameter, especially in sick children is very challenging for clinicians who frequently rely on indices such as long capillary refill times, tachycardia, central venous pressure and decreased urine volume as guides. Here, we present the UHAS-MIDA, an open-source software tool that calculates the red blood cell (RBC) concentration and blood volume during malaria in children determined using a stable isotope of chromium (53Cr as the label) by gas chromatography-mass spectrometry in selective ion monitoring (GC/MS-SIM) analysis. A key component involves the determination of the compositions of the most abundant naturally occurring isotopes of Cr (50Cr, 52Cr, 53Cr), and converting the proportions into a 3 × 3 matrix. To estimate unknown proportions of chromium isotopic mixtures from the measured abundances of three ions, an inverse matrix was calculated. The inverse together with several inputs is then used to calculate the corrected MS ion abundances. Thus, we constructed the software tool UHAS- MIDA using HTML, CSS/Bootstrap, JavaScript, and PHP scripting languages. The tool enables the user to efficiently determine RBC concentration and fluid volume. The source code, binary packages and associated materials for UHAS-MIDA are freely available at https://github.com/bentil078/Abaye-et-al_UHASmida

Trophic Ecology of Sharks in the Mid-East Pacific Ocean Inferred from Stable Isotopes

As apex predators, sharks are of ecological and conservation importance in marine ecosystems. In this study, trophic positions of sharks were estimated using stable isotope ratios of carbon and nitrogen for five representative species caught by the Chinese longline fleet in the mid-east Pacific, i.e., the blue shark （Prionace glauca）, the bigeye thresher shark （Alopias superciliosus）, the silky shark （Carcharhinus falciformis）, the scalloped hammerhead （Sphyrna lewini）, and the oceanic whitetip shark （Car-charhinus longimanus）. Of these species, oceanic whitetip shark has the lowest trophic level and mean 815N value （3.9 and 14.93%o± 0.84%o）, whereas bigeye thresher shark has the highest level/values （4.5 and 17.02%o±1.21%o, respectively）. The bigeye thresher shark has significantly higher 515N value than other shark species, indicating its higher trophic position. The blue shark and oceanic whitetip shark has significantly higher 813C values than bigeye thresher shark, silky shark and scalloped hammerhead, possibly due to different diets and/or living habitats. The stable isotope data and stomach content data are highly consistent, suggesting that sta-ble isotope analysis supplements traditional feeding ecology study of sharks, and thus contributes to understanding their trophic linkage.

Trophic ecology of small yellow croaker (Larimichthys polyactis Bleeker): stable carbon and nitrogen isotope evidence

The trophic ecology of the small yellow croaker （Larimichthys polyactis） was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios （~3C） ranged from -20.67 to -15.43, while stable nitrogen isotope ratios （~SN） ranged 9.18-12.23. The relationship between fi^3C and ~SN suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes （such as ocean current, wind and tide） and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits.

Effects of pretreatment procedures on fatty acid composition and stable carbon isotopes in the marine microalga Isochrysis zhanjiangenisis

This study aims to quantify the effects of different pretreatment methods on the stable carbon isotope values of fatty acids in marine microalgae（Isochrysis zhanjiangenisis）.To identify the effects of sample preparation on theδ^（13）C value and the fatty acid composition,we examined eight types of pretreatment methods including：（a） drying the sample followed by direct methyl esterification using HCl-CH3OH;（b） drying the sample followed by direct methyl esterification using H2SO4-CH3OH;（c） drying the sample by ultrasonic extraction and methylesterification using HCl-CH3OH;（d） drying the sample by ultrasonic extraction and methyl-esterification using H2SO4-CH3OH;（e） fresh sample followed by direct methyl-esterification using HCl-CH3OH;（f） fresh sample followed by direct methyl-esterification using H2SO4-CH3OH;（g） fresh sample with ultrasonic extraction followed by methyl-esterification using HCl-CH3OH,and（h） fresh sample with ultrasonic extraction followed by methylesterification using H2SO4-CH3 OH.The results show that the δ^（13）C values from Groups a-e,g and h fluctuated within 0.3‰,and the δ^（13）C values of Group f were approximately 0.7‰ lower than the other seven groups.Therefore,the different sample pretreatment methods used towards the extraction of fatty acids from marine microalgae may result in different results regarding the stable carbon isotope ratios,and if necessary a correction should be applied.

Oxygen Stable Isotopic Ratio in Precipitations in Niigata Prefecture, Japan

Time-course of oxygen stable isotopic ratios （i.e., δ^18O） as well as seasonal variation of δ^18O has been examined to investigate the characteristics, sources and the passing route of precipitations in Niigata Prefecture. The precipitation samples have been mainly collected with a filtrating bulk sampler at the rooftop of Niigata University. Furthermore, backward trajectories analyses have been also conducted for these samples taken sequentially for a short period. Consequently, the following features have been mainly clarified for the precipitations in Niigata Prefecture： （1） the δ^18O values varied between -14.57%o and -3.86%0 in the precipitations of Niigata University; （2） as for the comparison among sampling points, the mean value of δ^18O at seaside spots （i.e., Niigata City： -6.93%0） is larger than that of inland spots （Sanjyo City： -8.68%0）; （3） δ^18O value was generally small in the rainy or typhoon season, and relatively large in summer; （4） decreasing δ^18O content with time is a predominant feature of sequentially sampled rainfalls as predicted by Rayleigh models of atmospheric vapor condensation.

Multivariate statistical analysis of chemical and stable isotopic data as indicative of groundwater evolution with reduced exploitation

Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)project.To identify groundwater evolution in this complex context,hierarchical cluster analysis(HCA)and principal component analysis(PCA)were combined to interpret an integrated dataset of stable isotopes and chemical data from four sampling campaigns in a pilot area of groundwater control.We proposed a novel HCA approach integrating stable isotopes and chemical signals,which successfully partitioned the groundwater samples into the unconfined and the confined water samples.Stable isotopic evidence showed that the lateral inflow and the surface water may contribute more to groundwater recharge in this region than local modern precipitation.The unconfined water's main hydrochemical types were Na type with mixed anions,and Na-Cl-SO_(4)type,while the confined water was mainly Na-Cl and Na-SO_(4)types.Geochemical processes mainly involved the dissolution/precipitation of halite,gypsum,Glauber's salt,feldspar,calcite and dolomite,as well as the cation exchange.PCA results showed that water-rock interaction(i.e.,salinity-based and alkalinity-based processes)predominated the hydrochemical evolution,along with local nitrate contamination resulting from fertilizers and domestic sewage.The GWER project regulated the natural evolution of unconfined water chemistry,and significantly reduced the unconfined water's salinity(mainly Na^(+),Mg^(2+),SO_(4)^(2-)).This may be attributed to upward leakage from low-salinity confined water at some parts of the aquifer.Additionally,insignificant changes in the confined water's salinity reflected that the impact of GWER on the confined aquifer was negligible.This study facilitates the groundwater classification effectively in the areas lack of geological data,and enhances the knowledge of groundwater chemical evolution in such a region where groundwater restoration is in progress,with important implications for groundwater sustainable management in similar basins worldwide.

Preliminary attempt to distinguish the domesticated pigs from wild boars by the methods of carbon and nitrogen stable isotope analysis

Despite great achievements in the origins of domestic pigs made by the methods of zooarchaeology and molecular biology,how to scientifically distinguish the domesticated pigs from wild boars during the early stage of pig domestication is still poorly understood.Compared to wild boar's diets which come from the natural environment,the diets of domestic pigs are more easily influenced by human feeding activities.Therefore,in principle,exploration of the dietary differences among pigs and understanding the impact on pig diets fed by humans can have great potential to differentiate between wild boars and domesticated pigs.To reveal dietary differences among pigs and distinguish the domesticated pigs from wild boars based on comparison with the diets of humans and other animals,we analyzed the carbon and nitrogen stable isotopes of human bones from Xiaojingshan Site and animal bones from Yuezhuang Site,both of which belong to Houli Culture in Shandong Province and date to about 8500―7500 years ago.The mean δ 13C value((-17.8 ± 0.3)‰) and δ 15N value((9.0±0.6)‰) in human collagen indicate that although millet agriculture began it was not the main subsistence strategy as millets are typical of C4 plants and that humans made a living mainly by gathering,hunting or raising some domesticated animals.The δ 13C value(-16.1‰) and δ 15N value(6.9‰) in the bovine suggest that C3 plants were dominant in its diet with some C4 plants complemented.The fish has lower δ 13C value(-24.9‰) and higher δ 15N value(8.8‰) than the bovine,which is the characteristic of the isotopic values from Eurasian freshwater fish.Based on the differences in carbon and nitrogen isotope values,the pigs can be divided into three groups.A group,composed of two pigs,has low δ 13C values(-18.1‰,-20.0‰) and low δ 15N values(4.7‰,6.0‰).B group,only one pig,has the highest δ 13C value(-10.6‰) and mediate δ 15N value(6.4‰).As for the C group,also only one pig,low δ 13C value(-19.0‰) and the highest δ 15N value(9.1‰) are observed.Previous studies on the stable isotopes from modern or ancient wild boars' bones have suggested that C3 plants are predominated in their diets and that their δ 15N values are close to those in herbivores and far from those in carnivores.Based on the comparison with the isotope values from humans,the wild boars and the domestic pigs from Xipo Site in Henan 6000―5500 years ago and Kangjia Site in Shaanxi 4500―4000 years ago,we conclude that A pig group belongs to wild boars while B and C groups can be attributed to domesticated pigs.

C and N stable isotope analysis of human and animal bones at the Beiqian site

The Beiqian site,located in Jimo city,Qingdao,went through three archaeological excavations,and a large number of human and animal bones in the Dawenkou culture and the Zhou Dynasty period were unearthed.By carbon and nitrogen stable isotope analysis,the diet of ancestors is expected to be recovered,and the domesticated plants and animals will be discussed.The investigated results showed that the food structure of ancestors in both periods included food crops,mainly C4 foods,and meat,mainly marine shellfish and livestock.For domestic pigs,they mainly eat C3 plants,and were affected by the lifestyle of ancestors.This study also showed that the diet of ancestors is the shellfish rather than marine fish despite the Beiqian site is located near the shoreline.We can conclude that the diet of ancestors in Dawenkou culture period included millet crops(C4plants),shellfish,marine food,and livestock,representing the lifestyle of farming,domestication,and fishing,supplemented by hunting.In the Zhou dynasty period the meat resource was enriched by domesticated animals and marine fisheries,and the living conditions were significantly improved.

Proteomic analysis of energy metabolism and signal transduction in irradiated melanoma cells

AIM: To analyze proteomic and signal transduction alterations in irradiated melanoma cells. METHODS: We combined stable isotope labeling with amino acids in cell culture (SILAC) with highly sensitive shotgun tandem mass spectrometry (MS) to create an efficient approach for protein quantification. Protein protein interaction was used to analyze relationships among proteins. RESULTS: Energy metabolism protein levels were significantly different in glycolysis and not significantly different in oxidative phosphorylation after irradiation. Conversely, tumor suppressor proteins related to cell growth and development were downregulated, and those related to cell death and cell cycle were upregulated in irradiated cells. CONCLUSION: Our results indicate that irradiation induces differential expression of the 29 identified proteins closely related to cell survival, cell cycle arrest, and growth inhibition. The data may provide new insights into the pathogenesis of uveal melanoma and guide appropriate radiotherapy.

Geochemical Modeling and Statistical Analysis for Groundwater Evolution Assessment in Wadi Qasab, Sohag, Eastern Desert, Egypt

Qasab basin is one of the most promising areas for the sustainable development in the Eastern Desert fringes of the Nile Valley, Egypt. The integration between statistical analysis, stable isotopes as well as geochemical modeling tools delineated the geochemical possesses affecting groundwater quality and detected the main recharge source in Qasab basin. The most of groundwater samples are brackish (88%), while the minority (12%) of the samples are fresh. The electrical conductivity of groundwater ranged from 1135 to 10,030 μS/cm. The statistical analysis and hydrochemical diagrams suggest that the groundwater quality is mainly controlled by several intermixed processes (rock weathering and agricultural activities). The mineralization of the Pleistocene groundwater is regulated by the rock weathering source, evaporation processes and reverse cation exchange. The isotopic signatures (δ2H and δ18O) represent two groundwater groups. The first group, is enriched with the isotopic signature of δ18O, which ranges from 0.9‰ to 5.5‰. This group is mostly affected by the recent meteoric recharge from the surface water leakage. The second group, is relatively depleted with the isotopic signature of δ18O, reflecting a palaeo recharge source of colder climate. The δ18O‰ varies from -10.1‰ to -6.4‰, indicating upward leakage of the Nubian sandstone aquifer through deep seated faults. The inverse geochemical model reflects that the salinity source of the groundwater samples is due to the leaching and dissolution processes of carbonate, sulphate and chloride minerals from the aquifer matrix. This study can demonstrate the hydrochemistry assessment guide to support sustainable development in Qasab basin to ensure that adequate groundwater management can play to reduce poverty and support socioeconomic development.

水中硝酸盐氮稳定同位素比值测定前处理方法的优化

水体中过量的硝酸盐会导致严重的水生生态恶化和环境污染问题。氮稳定同位素技术为水体污染来源的判断及水生系统氮素转化机理研究提供了强有力的工具。在前人基础上,通过开发Cu^(2+)-Cd复合催化结合超声波辅助加速反应,优化硝酸盐氮同位素比值测定前处理方法。考察了Cu^(2+)添加量、超声功率以及反应时间变化对NO_(3)^(-)-N转化生成N_(2)O气体及其氮同位素比值的影响,在单因素实验基础上采用正交实验优化得到了最佳反应条件,并采用不同^(15)N同位素比值的KNO_(3)标准溶液结合气体预浓缩装置与稳定同位素质谱仪联用系统对新方法进行了验证。新方法单次反应体系中氮最低量为1.0μg,其中自然丰度和高丰度样品δ^(15)N分析精度小于1‰,富集样品的^(15)N分析精度可达0.1 atom%以内(CV<1%);且所有标准样品的^(15)N测定值与参考值基本一致。将优化后的方法应用于不同来源水样中硝酸盐氮稳定同位素比值测定,均可获得较好的精度,较原方法提高了前处理效率,且精度更优。建立的方法准确可靠,操作简单,耗时短,适用于水中硝酸盐氮稳定同位素比值测定的批量、快速前处理。

Stable isotopic analysis on ancient human bones in Jiahu site

Palaeodietary analysis is one of important topics in bioarchaeology field and has been paid great at- tention to by Chinese archaeometrists recently. Ancient human bones in Jiahu Site were analyzed by means of stable isotopes of C, N and O. 13 human bones were excluded from 28 bones for dietary re- construction due to their unusual collagen contents, C and N contents, and C/N atomic ratios espe- cially. δ 13C (-20.37±0.53‰) in collagen of remaining samples showed that C3 food were consumed mainly, which is consistent of the archaeological findings that rice was the staple in Jiahu. According to the difference of δ 15N and δ 13C values in bone collagen, the samples can be classified into four clusters. The changes of δ 15N values in bone collagen and δ 13C values in hydroxylapatite through whole cultural phases indicated the transition from hunting to gathering and fishing to rice agriculture and animal domestication ultimately. Meanwhile, the δ 18O change in hydroxylapatite showed that pa- laeoclimate was relatively constant during Jiahu culture.

元素分析-稳定同位素比质谱联用仪日常使用及常见故障排除方法

介绍了元素分析-稳定同位素比质谱联用仪的工作原理,总结了该仪器的日常使用技巧,提出了元素峰面积异常、系统检漏、系统堵塞、加热炉环境温度太高、球阀拆洗、离子源清洗等常见故障的排查方法,供仪器设备管理员和分析测试人员参考使用。

Stable isotopic analysis on sus bones from the Wanfabozi site, Tonghua, Jilin

In order to study the sus diets and explore the possibility to distinguish domestic pig from wild boar through dietary analysis, stable carbon and nitrogen isotopes of 28 pig bones from archaeological site of Wanfabozi in Tonghua City, Jilin Province were analyzed. The δ 13C and δ 15N values of uncontaminated bones show that the overall pigs in the site were generally herbivores and ate mainly C3 plants. Significant difference of δ15N values was observed between wild boar and domestic pigs, which may result from the higher consumption of animal protein in domestic pigs other than from that in wild boar, possibly from human leftover or waste,. The dietary difference between wild boar and domestic pigs has great potential to differentiate wild boar and domestic pigs in the early stage of pig domestication.

基于瓜籽稳定同位素与多元素分析的甜瓜产地溯源研究

目的探索一种基于瓜籽稳定同位素及多元素分析的甜瓜产地溯源新策略,克服高糖甜瓜样本冻干预处理困难的难题,提升甜瓜溯源的可操作性与稳定性。方法采集新疆、广西、海南3个省份58个甜瓜样本,并测定其瓜籽的碳、氮、氢、氧稳定同位素比率与16种矿物元素含量。首先,利用单因素方差分析比较不同省份甜瓜样本的区域差异。并进一步通过构建瓜籽稳定同位素及元素特征的线性判别分析模型区分不同产地的样本。结果单因素方差比较证实甜瓜的4种稳定同位素比率与部分元素含量特征在不同产地间具有显著的差异(P<0.05),线性判别分析模型实现3个省份甜瓜样本的准确判别,整体留一法交叉验证准确度高达96.5%。结论该策略能够有效地区分新疆甜瓜与其他省份的甜瓜,有望作为保护新疆甜瓜品牌信誉,确保新疆甜瓜产业健康发展的有用工具。

基于多源多维数据融合分析的新疆甜瓜产地溯源研究

为实现新疆县市级地理尺度间甜瓜原产地溯源,本研究以新疆15个县市主产区的239份甜瓜样本为对象,分析样本稳定同位素、多元素、^(1)H核磁波谱特征;通过偏最小二乘判别分析建模提取多源数据中的主要贡献变量。结果表明,δ^(2)H、Al、P、Na、δ^(18)O和^(1)H核磁共振波谱中化学位移(δ)为2.5528和2.5253时的响应信号为最重要的判别变量(VIP>1);单独应用稳定同位素及多元素、核磁共振波谱建模,总体判别准确度分别为85.8%和72.8%,难以满足溯源应用的要求;多源多维数据融合建模可提升甜瓜判别准确度至95.8%,能够实现县市级微观地理尺度间的新疆甜瓜溯源。本研究可为新疆甜瓜原产地确证与地理标志产品品牌保护提供技术支持。

吐鲁番盆地平原区地下水水化学成因机制及灌溉适宜性

在新疆吐鲁番盆地平原区共采集52组地下水水样和7组地表水水样,综合运用水化学法、氢氧稳定同位素、正演模型(FM)和因子分析等方法,定性-定量揭示了地下水溶质来源及水化学的影响因素,并进行灌溉水质评价.结果表明:北盆地浅层地下水属中性-弱碱性,而南盆地浅层地下水、深层地下水均呈弱碱性;优势阴、阳离子均分别为SO_(4)^(2-)和K^(+)+Na^(+).大气降水是研究区地下水的主要补给来源,与北盆地浅层地下水和南盆地深层地下水相比,南盆地部分浅层地下水受到一定的蒸发作用影响.地下水溶质来源主要受控于岩石风化作用,以蒸发盐岩为主;河流输入、人类活动和岩石风化分别对北盆地浅层地下水、南盆地浅层地下水及南盆地深层地下水溶质的相对贡献为(10.23%,1.25%,88.52%)、(10.72%,0.66%,88.62%)和(5.30%,0.44%,94.26%).吐鲁番盆地浅层地下水水化学主要受到溶滤-蒸发作用(54.31%)和农业活动-有机质含量(35.36%)的影响,而溶滤作用(58.96%)和环境(28.97%)2个因子为南盆地深层地下水水化学特征的主控因素.南盆地深层地下水基本适合灌溉,北盆地浅层地下水受高EC值以及南盆地浅层地下水受高EC值和高%Na的共同影响,导致部分地区不适合灌溉.