中国东部南北样带森林生态系统WUE和NUE空间格局及驱动因子(英文)   总被引：4，自引：1，他引：3  

盛文萍  任书杰  于贵瑞  方华军  姜春明  张弥 《地理学报(英文版)》2011,21(4):651-665

From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China (NSTEC). Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency (WUE) and nitrogen use efficiency (NUE), and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed: (1) vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. (2) Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE (p<0.001). While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE (p<0.001). Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. (3) There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC (p<0.001), indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.  相似文献   

长江流域大气降水中δ^18O变化与水汽来源   总被引：1，自引：0，他引：1  

吴华武  章新平  孙广禄  申林  黄一民  王红红 《辽宁气象》2011,(5):7-12

根据GNIP所提供的长江流域多年月平均降水中δD、δ^18O料以及NOAA-CIRES提供的NCEP/NCAR再分析资料,研究了长江流域降水稳定同位素与降水量、水汽压、温度和水汽来源之间的关系。结果表明：在平均季节尺度下,长江流域大气降水中δ^18O降水量、水汽压和温度均存在显著的负相关关系,说明该流域降水中δ^18O化存在显著的降水量效应、湿度效应和反温度效应。基于降水中过量氘示踪水汽来源原理,分析了中国长江流域季风区降水中过量氘与阿拉伯海、孟加拉湾和南印度洋3个海区相对湿度的关系,表明中国长江流域的水汽主要来源于上述3个海区,而昆明和成都可能受到其他水汽作用,使其与水汽源区的相对湿度呈正相变化。  相似文献   

咸化水体中DIC的同位素组成及环境过程分析   总被引：3，自引：0，他引：3  

王中良  李军  刘丛强  朱兆洲  李勇 《地球化学》2011,(6):552-558

系统采集了天津地区地表水样品,对其溶解无机碳的稳定碳同位素比值(δ13CDIC)及相关化学组成进行了全面测定,以期对咸化并且受到污染水体中的溶解无机碳的来源和迁移转化特征进行探讨.研究结果显示,天津地表水中溶解无机碳的δ13CDIC值主要分布于0.27‰～ -14.9‰之间,显示了相对较宽的分布范围.同时,天津地表水体...  相似文献   

贵阳大气降水硫同位素地球化学特征   总被引：7，自引：0，他引：7  

肖红伟  肖化云  龙爱民  王燕丽 《地球化学》2011,(6):559-565

对贵阳地区2008年10月1日至2009年9月30日降水样品的SO42-含量和δ34S进行了测定.结果表明,研究时段内降水SO42-浓度为13.2 mg/L,δ34S值的变化范围为-12.0‰～+9.4‰,年均值为-2.8‰±1.4‰,主要来源于燃煤释放的含硫物质.大气降水SO42-浓度和δ34S值存在明显的季节性变化...  相似文献   

高精度硅同位素分析方法研究进展     

王俊霖  王微  魏海珍 《高校地质学报》2021,27(3):275-288

基于碱熔法的改进和多接收电感耦合等离子质谱仪（MC-ICP-MS）的发展,近年来高精度Si同位素组成（δ30Si）分析方法取得了长足进步,分析精度（2SD）自气体质谱仪（GS-MS）时代的±0.15‰~±0.30‰ 提高到优于±0.10‰,足以辨析高温过程中Si同位素发生的微小分馏,并且避免了实验流程中使用含氟等危险化学品。二次离子质谱（SIMS）和飞秒激光剥蚀（fs LA）的发展使得原位Si同位素组成分析精度近期也优化到±0.10‰~±0.22‰。文章对近年来Si同位素分析方法的发展沿革进行综述,探讨建立溶液法MC-ICP-MS的高精度Si同位素分析方法的进展与局限,并比对了国内外各个实验室已发表国际国内Si同位素标准物质测定值,最后总结了硅酸盐地球（BSE）、地壳和陨石等主要地质储库的δ30Si组成范围。  相似文献   

Seasonal variations in the isotopic composition of leaf and stem water from an arid region of Southeast Asia     

Saira Butt  Mubarik Ali  Muhammad Fazil  Zahid Latif 《水文科学杂志》2013,58(5):844-848

Abstract

Stable isotopes are powerful research tools in environmental sciences and their use in ecosystem research is increasing. Stable isotope measurements allow the study of evapotranspiration fluxes, soil evaporation and leaf transpiration phenomena. Soil water and leaf water are the sources of the evapotranspiration that transfers large quantities of water from land to the atmosphere; as a result the isotopic composition of water left in the leaves is modified towards enrichment. Evaporation also changes the isotopic composition of water bodies creating a natural isotopic signal. The isotopic identity of soil water affects the oxygen isotopic signature of leaf and stem water. In this paper we present the isotopic data of bulk leaf water, showing the enrichment in isotopic value of oxygen due to evapotranspiration from leaves in conjunction with the isotopic signal of rainwater and other environmental factors such as humidity and temperature. Results suggest that the variation in the values of δ¹⁸O of Eucalyptus citriodora, Dalbergia sissoo, Melia azedarach and Pinus roxburghii is due to the seasonal changes in the δ¹⁸O of the source water for plants, i. e. rain. It is further observed that leaf water δ¹⁸O values are depleted during the months of July, August and September. This occurs due to the following reasons: (a) the sampling areas receive about 50% of the average annual rain during these months, and (b) rainfalls during these months are isotopically depleted compared with winter rains.

Citation Butt, S., Ali, M., Fazil, M. & Latif, Z. (2010) Seasonal variations in the isotopic composition of leaf and stem water from an arid region of Southeast Asia. Hydrol. Sci. J. 55(5), 844–848.  相似文献   

Mt. Suhora M dwarf survey - Detection of eight short-period variable stars     

L. Fox Machado  A.S. Baran  M. WiniarskiJ. Krzesiński  M. Dró?dz 《New Astronomy》2012,17(2):65-72

The Mt. Suhora M dwarf survey searching for pulsations in low mass main sequence stars has acquired CCD photometry of 46 M dwarf stars during the first year of the project (Baran et al., 2011). As a by-product of this search hundreds field stars have been checked for variability. This paper presents our initial result of a search for periodic variables in field stars observed in the course of the survey. On the basis of the periodicity and the shape of the light curves, eight new variables has been detected, among which five are δ Scuti stars and three likely RR Lyrae stars. Although variation in one of the stars has been previously detected, it was classified incorrectly. To support our classification, in August 2010, we performed spectroscopic observations to derive spectral types and luminosity classes for all eight variable stars.  相似文献   

溢油污染物在海底沉积物中的识别与垂向迁移——大连湾海底沉积物研究          下载免费PDF全文

于晓果  杨海丽  刘星  雷吉江  林忠胜  姚子伟  章伟艳  姚旭莹  金肖兵 《海洋学研究》2018,36(1):58-65

沉积物插管短柱样品于2013年4月采自大连湾2010年“7·16”溢油事故污染区,BQ050站与BQ007站分别位于生物分散剂和化学分散剂喷洒区。沉积物的可溶有机质含量(沥青A)、有机碳同位素组成(δ¹³C_org)和²¹⁰Pb比活度分析结果表明:喷洒生物分散剂的重污染区(BQ050站),沉积物中TOC含量为0.58%～1.51%,平均为1.15%;δ¹³C_org值为-22.2‰～-20.5‰PDB,平均为-21.74‰PDB;沥青A含量为0.061 5%～0.566 4%,平均为0.174 9%;沥青A/TOC比值为7.0%～34.8%,平均为14.13%;²¹⁰Pb_ex比活度存在异常峰值分布,垂向分布特征与沥青A相似;2～16 cm段沉积物的可溶有机质具有明显的外来输入特征。喷洒化学分散剂的较轻污染区(BQ007站),沉积物中TOC含量为0.61%～1.14%,平均为0.87%,除8～14 cm层段外,比BQ050站略低;但沥青A含量与沥青A/TOC比值明显低于前者;δ¹³C_org值较BQ050站轻;²¹⁰Pb_ex比活度随柱样深度呈指数衰减,对数相关;外来有机质输入量较低。截至2013年4月,BQ050站溢油污染物在海底下16 cm深度处有特征信号,溢油污染物沥青A 组分垂向迁移距离约为15 cm。  相似文献   

基于脂肪酸标记法和碳氮稳定同位素比值法的东海水母常见种的食性分析   总被引：1，自引：0，他引：1  

金鑫  李超伦  刘梦坛 《海洋与湖沼》2012,43(3):486-493

采用脂肪酸标记法和碳氮稳定同位素比值法研究了东海6个水母常见种的食性。结果表明,6种水母的总脂肪酸含量都不高,说明作为饵料,水母不能够给捕食者提供较多的脂类营养物质。蝶水母(Ocyropsis crystallina)、瓜水母(Bero cucumis)和四叶小舌水母(Liriope tetraphylla)的脂肪酸组成较为相近,它们更多地通过捕食食物链获得有机质。同时,这几种小型水母摄食浮游植物(主要是硅藻和甲藻)比其它几种水母多;另外,它们对植食性桡足类也有一定的摄食。4月份墨绿多管水母(Aequorea coerulescens)主要通过腐生食物链获取有机质;另外,其对植食性桡足类也有一定的摄食。双生水母(Diphyidae spp.)参与腐生食物链也较多;另外,20:1+22:1含量较低指示了其对植食性桡足类几乎不摄食。蝶水母、瓜水母、四叶小舌水母和沙海蜇(Nemopilema nomurai)的δ13C更接近于陆源的C4植物的δ13C,说明其受陆源影响较大。δ15N特征结果表明,蝶水母、瓜水母和四叶小舌水母(Liriope tetraphylla)在浮游食物网中均处于较高营养级,沙海蜇虽个体较大,但由于其摄食器官较小,故其与这3种小型水母的营养地位相近。并且相对于其它几种水母,沙海蜇细菌脂肪酸标记更为明显。  相似文献   

基于TES 反演数据的亚洲中低纬度地区大气水汽δD 的时空分布   总被引：1，自引：0，他引：1  

黄一民  孙葭  黄一斌  章新平 《地理学报》2014,69(11):1661-1672

利用搭载在Aura 卫星上的TES 观测仪所反演的2004 年8 月至2010 年12 月逐日HDO、H₂O、气温以及GNIP等资料,对亚洲中低纬度地区大气水汽中δD的时空分布特征、水汽δD与气温、水汽量的关系以及与降水同位素的关系进行了研究。从空间上来看:大气水汽、降水δD整体上表现出随纬度升高而降低的趋势,同时低纬度的西太平洋暖池以东和西亚地区形成了两个高值中心,中纬度的青藏高原和西太平洋形成了两个低值中心。从季节变化来看:陆地上水汽δD表现出暖季的高值与冷季的低值交替出现,海洋上这种变化则不明显,同时,可以看到水汽δD的季节变化与低纬度陆地上降水δD的暖季低、冷季高正好相反;中纬度大陆上水汽δD的最大值出现在气温最高的夏季;低纬度的印度半岛、中南半岛的最大值出现在季风暴发前的春季。就水汽中δD与气温、水汽量关系而言:在中纬度大陆及西亚地区均表现出正相关;在西太平洋暖池处,水汽中δD与气温呈正相关,与水汽量呈负相关。  相似文献