农业活动对岩溶作用碳汇的影响:以重庆青木关地下河流域为例   总被引：6，自引：0，他引：6  

张兴波  蒋勇军  邱述兰  曹敏  胡毅军 《地球科学进展》2012,27(4):466-476

以受农业活动影响强烈的重庆青木关地下河流域为研究对象,利用CTDP300多参数水质自动记录仪、WGZ-1型光电数字水位计、HOBO小型气象站在线自动监测电导率、水位以及降雨等数据,并获取流域耕地面积数据,于2010年分月采集地下水样,分析常规水化学和地下水溶解无机碳δ13C,初步探讨流域农业活动对岩溶作用过程和碳汇的影响,发现农业活动对岩溶作用过程产生明显的影响,进而影响到岩溶地质碳汇。地下水水化学以及地下水δ13CDIC值证实了流域地下水DIC是碳酸、硝酸和硫酸共同溶蚀碳酸盐岩的产物;每月碳酸溶蚀碳酸盐岩产生DIC占地下水中总DIC的比例在55.53%～81.25%之间,雨季(62.98%)普遍低于旱季(74.86%);碳酸溶蚀碳酸盐岩产生的DIC的量为14.67×106mol/a,其中岩溶作用产生的净CO2汇量为7.335×106mol/a,而硝酸和硫酸溶蚀碳酸盐岩产生的DIC总量为7.48×106mol/a,约占地下水中总DIC的33.8%,单位面积耕地上硝酸和硫酸溶蚀碳酸盐岩产生DIC的强度为1.89×106mol/(km2.a)。人类活动引入的硝酸和硫酸参与碳酸盐岩的溶解并改变了区域碳循环。  相似文献   

四川攀西地区某铜铅多金属硫化矿选矿试验研究     

唐程 《四川地质学报》2013,(2):162-165

该处矿石铜铅分离时沿用重铬钾(K2Cr2O7)抑铅,由于重铬酸钾的使用产生了大量含铬(Cr6+)废水,严重地污染了周围的环境。受企业委托选用了无毒、无污染的选矿药剂,代替重铬酸钾。试验研究结果表明,用无毒巯基乙酸钠抑铜浮铅,可实现铜铅分离,并可获得较好的浮选指标。  相似文献   

Heavy-metal loadings related to urban contamination in the Kooloonbung Creek catchment,Port Macquarie,New South Wales     

P. M. Ashley  M. E. Napier 《Australian Journal of Earth Sciences》2013,60(6):843-862

Urbanisation and industrial development lead to contamination of estuaries and streams with dispersed loadings of heavy metals and metalloids. Contributions of these elements also occur from natural sources. This study provides baseline geochemical data on the respective natural and anthropogenic inputs of Cu, Pb, Zn, Cd, As, Sb, Cr, Ni, Mn and S to estuarine, fluvial and wetland sediments, and adjacent soils, in the Kooloonbung Creek catchment that drains the Port Macquarie urban area in north coastal New South Wales. There have been anthropogenic additions of Cu, Pb, Zn and As from dispersed urban sources at Port Macquarie, but they are restricted to the local catchment and do not impact on the adjacent Hastings River estuary. The most contaminated sediments display enrichment factors up to 20 × for Cu and Pb, 9 × for Zn and 5 × for As relative to local background values. However, only one value (for Pb) exceeds National Water Quality Management Strategy interim sediment quality guideline (high) values. On the other hand, sediments and local soils are commonly strongly enriched in Cr, Ni and Mn, reflecting adjacent ultramafic and mafic rock substrate and lateritic regolith. Concentrations of Cr and Ni are commonly well above interim sediment quality guideline (high) values for sediments, but are in mineralogical forms that are not readily bioavailable. Sediment and soil quality guideline values consequently need to recognise natural enrichments and the mineralogical siting of heavy metals. Although dissolved concentrations of heavy metals in stream waters are commonly low, there is evidence for mobility of Cu, Zn, Fe and Al. Parts of the Kooloonbung Creek wetland area lie on sulfidic estuarine sediments (potential acid sulfate soils). Experimental oxidation of uncontaminated and contaminated sulfidic sediments leads to substantial dissolution of heavy metals under acid conditions, with subsequent aquatic mobility. The results warn about disturbance and oxidation of potential acid sulfate soils that have been contaminated by urban and natural heavy-metal sources.  相似文献   

Electron spin resonance dating of Quaternary bone material from Tasmanian caves—A comparison with ages determined by aspartic acid racemization and C14     

A. Goede  J. L. Bada 《Australian Journal of Earth Sciences》2013,60(2):155-162

Abstract

Fourteen bone samples are analysed to test the usefulness of equivalent dose (ED) determinations by electron spin resonance (ESR) as a rapid method of determining relative age and making an estimate of absolute age. ED values are compared with eight aspartic acid dates and two C¹⁴ dates. The latter are dates on charcoal found in close association with bone at archaeological sites. For samples less than 25 000 years old an excellent correlation is obtained when ED values are compared with dates obtained by the other two methods. The relationship suggests that ED values can be converted to estimates of bone age by assuming a mean annual dose rate of 0.1 rad/yr. Age determinations provide little evidence to support earlier suggestions that elements of the Late Pleistocene megafauna survived until the end of the Pleistocene. Bone material at some sites in the‐Florentine Valley and near Montagu appears to be much older than had previously been believed. Only one site (Main Cave, Montagu) containing megafaunal elements appears to be terminal Pleistocene in age but the possibility of reworking of megafauna material from nearby older sites cannot be excluded. ESR dating has considerable potential as an exploratory dating tool but can only be applied to dense, unaltered bone samples. Attempts to analyse five samples from Kutikina Cave in Western Tasmania were unsuccessful because of post‐depositional contamination of the bone.  相似文献   

降尘矿物在柠檬酸中的溶出顺序研究     

唐俊  董发勤  代群威  邓跃全  陈武 《岩石矿物学杂志》2013,32(6):857-862

针对自然降尘进行的物相、成分分析表明该降尘的物相组成非常复杂,以石英、方解石、钠长石、白云石、云母为主要物相成分。为探讨降尘中矿物在有机酸中的溶解情况,进一步揭示其对人体的危害程度。本文以西宁降尘为研究对象,并选择柠檬酸为代表有机酸,分别用XRD、FTIR及ICP-AES等方法对柠檬酸处理前后降尘的残余固体及反应上清液进行分析。结果表明,降尘中方解石在经柠檬酸作用10 min后完全溶解,白云石在16 h内基本溶解完全,根据红外分析结果,Si—O、Al—O结构未发生明显破坏。然而,溶出元素结果显示,Al、Si的溶出量随着溶解时间的增长而缓慢增加,说明柠檬酸对Si—O四面体及Al—O八面体也造成了一定的破坏作用。通过分析降尘中3种难溶矿物在相同条件下的溶解速率可以得出,在整个溶解过程中,钠长石的溶解速率高于绢云母,而石英的溶解速率在不同的溶解时间有着较大的差异。根据3种纯矿的溶解速率推断三者的溶解顺序,钠长石明显先于云母溶解,石英的溶解先后顺序还有待进一步研究。通过降尘及纯矿在柠檬酸中溶解过程中不同时刻的元素溶出比例及矿物溶出速率可以得出除石英外4种主要矿物的溶解顺序为:方解石,白云石,钠长石,绢云母。  相似文献   

Pecten as a new substrate for IcPD dating: The quaternary raised beaches in the Gulf of Corinth,Greece     

《Quaternary Geochronology》2016

Intra-crystalline protein diagenesis (IcPD), a recent development of amino acid racemization dating (AAR), is now established as a reliable geochronological tool for the Quaternary. However, extending the method to new biominerals requires extensive testing in order to provide evidence for the closed-system behaviour of the intra-crystalline proteins and to assess the temporal span that can be covered.Here we present results from high-temperature experiments on the IcPD of the bivalve Pecten, demonstrating that a fraction of proteins can be isolated from a bleach-resistant mineral matrix, which effectively operates as a closed system under conditions of accelerated diagenesis in the laboratory. Analyses of Pecten from the well-dated terrace system of the Gulf of Corinth (Greece) provided a pilot test for the integrity of the intra-crystalline fraction in subfossil shells. The small sample sizes in this preliminary study preclude a full assessment of the aminostratigraphic power of Pecten IcPD, but a concordance is observed between the extent of IcPD and sites dating from between MIS 5 and MIS 11.We conclude that Pecten is a potentially good substrate for IcPD dating in the Mediterranean, and that the temporal limit of the technique in this area lies beyond MIS 11.  相似文献   

天然有机质对纳米零价铁去除水中六价铬的影响     

王恩泽  韦志伟  曹茜  颜泽龙  陈家玮 《现代地质》2016,30(4):818-824

应用纳米零价铁进行地下水污染治理是近年迅速发展的环境修复新技术,但在实际应用中,纳米零价铁的反应活性受到环境条件的影响,其中自然界中广泛存在的天然有机质就是重要影响因素。通过批实验研究腐殖酸(天然有机质代表物)对纳米零价铁去除水中六价铬的影响,结果表明,腐殖酸的存在能够极大地抑制纳米铁去除六价铬的反应速度和去除效率,原因在于纳米铁对腐殖酸具有一定的吸附作用,从而减少了纳米铁表面的有效活性位点,降低了对六价铬的作用。此外发现,水体中溶解氧的存在有利于纳米铁对六价铬的去除。关于腐殖酸-纳米零价铁-六价铬的相互作用研究,对于进一步揭示修复体系作用机制具有重要的理论和应用价值。  相似文献   

Responses in growth, lipid accumulation, and fatty acid composition of four oleaginous microalgae to different nitrogen sources and concentrations   总被引：1，自引：0，他引：1  

李涛  万凌琳  李爱芬  张成武 《中国海洋湖沼学报》2013,31(6):1306-1314

Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production.  相似文献   

α-萘乙酸钠对温室辣椒产量和内源激素水平的影响     

张红菊  赵怀勇  郁继华 《中国沙漠》2013,33(5):1390-1399

以陇椒2号为试验材料,研究了α-萘乙酸钠对荒漠区日光温室辣椒产量和内源激素水平的影响。结果表明:叶面喷施35 mg·L-1的α-萘乙酸钠显著提高了辣椒生育后期的单果重,降低了辣椒不同生育阶段的落花落果率,改善了辣椒植株的营养条件,加速了辣椒根系和地上部分中后期的生长速率和干物质积累量,提高了辣椒不同生育阶段单株的产量。单果重和单株平均产量较对照分别提高15.76%和43.18%,落花落果率较对照降低19.77%。叶面喷施30～35 mg·L-1的α-萘乙酸钠显著降低了辣椒植株生长过程中叶片内源激素脱落酸（ABA）和吲哚乙酸（IAA）的含量,而且浓度越高,效果越明显;改变了辣椒叶片内源激素赤霉素（GA）和玉米素（ZR）的浓度和分布。辣椒植株的单株产量与叶片内源激素ZR含量正相关,与IAA和ABA的含量负相关,与GA相关性不显著。  相似文献   

The occurrence of gold in hydrothermal sulfide at Southwest Indian Ridge 49.6°E   总被引：2，自引：0，他引：2  

YE Jun  SHI Xuef  YANG Yaomin  LI Naisheng  LIU Jihu  SU Wenchao 《海洋学报(英文版)》2012,31(6):72-82

Massive sulfide precipitates found in the Southwest Indian Ridge(SWIR) 49.6°E hydrothermal field are enriched in gold.Here,the mineralogy and mineral chemistry of these massive sulfides to constrain the process of gold precipitation were studied.Sulfide samples in this field include lowertemperature Zn-rich sulfides and relative higher-temperature Fe-rich sulfides.Zn-rich sulfides are dominated by sphalerite-pyrite-chalcopyrite assemblages,with concentrations of gold ranging from 9.08 to 17.0 μg/g.Fe-rich sulfides consist mainly of pyrite-marcasite-isocubanite assemblages,with gold concentrations from 2.17 to 3.79 μg/g.The significant enrichment in gold within the lowertemperature Zn-rich sulfides and the effective separation of Zn and Fe in hydrothermal precipitates at the surface of this field are here interpreted to reflect the strong temperature dependence of gold transportation and deposition within the sulfides.In Zn-rich samples,large amounts of isolated native gold grains were identified.They were found mainly as inclusions up to 8 μm in diameter,occupying porous cavities in sphalerite or in the elevated iron content rim of sphalerite.The fineness of the gold ranged from 810 to 830.Unlike previously published results on other hydrothermal fields,these data show a low gold fineness values in SWIR 49.6°E.The FeS content of sphalerite associated with gold grains ranged from 3.2 mole % to 18.9 mole %.This was higher than in other fields,indicating that the sulfur activity is relatively low during the gold precipitation process and that sulfur activity may be one of the main factors affecting gold fineness in the SWIR 49.6°E hydrothermal field.Evidence regarding gold fineness and sulfur activity suggests that gold was quite likely transported as AuHS0 rather than as a Au(HS)-2 complex.  相似文献