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81.
铅锌尾矿砂污染下的岩溶土壤微生物群落碳源代谢特征 总被引:2,自引:1,他引:1
以广西阳朔思的村铅锌矿尾砂污染的水稻田、玉米地、柑橘园以及对照(旱地)土壤为研究对象,采用碳素利用法和18S rRNA变性梯度凝胶电泳技术探究岩溶区重金属污染下土壤微生物群落碳源代谢特征以及土壤真菌与土壤有机碳的交互关系.结果表明,广西阳朔思的村铅锌矿尾砂污染区土壤重金属总体含量(Pb、Zn、Cu、Cd)依次为:水稻田玉米地柑橘园对照;同时地累积综合指数显示该区重金属污染以Pb、Cd为主,其中Cd带来的环境风险最高.受Pb、Zn、Cu、Cd等重金属复合污染物影响,土壤微生物生物量碳、微生物熵和碳源代谢速率表现出随总体重金属质量分数增加而降低的变化规律,但土壤总有机碳质量分数却表现为:水稻田对照柑橘园或玉米地.DGGE结果进一步显示对照组土壤存在担子菌门多孔菌目Pycnoporus sp.ZW02.30,柑橘园和玉米地土壤存在镰刀菌属Fusarium solani和Fusarium oxysporum以及柑橘园土壤存在青霉属Penicillium decumbens.然而,上述参与淀粉、纤维素、半纤维素、木质素等糖类降解过程的真菌没有在水稻田土壤检出.加之,水稻田土壤微生物功能多样性指数和微生物熵最低而土壤有机碳质量分数最高,说明铅锌尾矿砂通过影响不同样地土壤微生物糖类代谢过程,进而调节土壤碳在微生物特别是真菌作用下的矿化速率. 相似文献
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Sesbania rostrata is renowned for its stem nodulation, but the role of stem nodulation in the root nodulation and adaptation of S.rostrata to Pb/Zn-enriched tailings environment has been poorly understood.We investigated the effects of inoculating (with stem nodule treatment) and non-inoculating (without stem nodule treatment) Azorhizobium caulinodans on the growth, root nodulation, and N fixation of S.rostrata grown on three different types of soil substrata: Pb/Zn tailings, garden soil amended tailings, and garden soil.The results showed that plant height, stem basal diameter, biomass, chlorophyll content, nitrogen content and N-accumulation per plant were 2.3%-4.9%, 2.2%-7.7%, 27.8%-72.2%, 17.1%-23.5%, 12.3%-34.2%, and 43.1%-131.2% higher in treatments with stem nodule than those without stem nodule for the same soil substrate, respectively.With respect to soil substrata, all the measurements had consistently higher values in tailings than in amended tailings and garden soil, indicating that the poorer the soil condition, the greater the contribution of stem nodule.In contrast, the number and fresh weight of root nodules on plants without stem nodule were 6.9-11.6 times and 5.8-29.0 times higher than those with stem nodule, respectively, especially with respect to the plants grew on Pb/Zn tailings.In general, stem nodulation favored plant growth and nitrogen fixation of S.rostrata, but suppressed root nodulation.With the ability of stem and root nodulation, S.rostrata can be used as a pioneer plant species for remediation of Pb/Zn tailings. 相似文献
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花岗岩铀地球化学特征新认识——以赣南富城产铀花岗岩体为例 总被引:1,自引:0,他引:1
对富城花岗岩U、T h含量分析结果进行的频数统计分析表明富城花岗岩U的均值为8.92×1-0 6、众数为8.0×10-6、中位数为7.03×1-0 6,其概率密度曲线偏向高端呈右偏非对称分布(偏度系数CSK=1.10)。T h的均值、众数和中位数三者一致,分别为25.7×10-6,25.75×10-6,25.8×1-0 6,其概率密度曲线呈对称正态分布(偏度系数CSK=0.11)。核诱发裂变径迹研究查明富城花岗岩中铀有4种存在形式:(1)显微粒状铀矿物(晶质铀矿);(2)以类质同像形式存在于锆石、磷灰石等副矿物之中;(3)均匀分散赋存在造岩矿物晶格之中的结构铀;(4)沿造岩矿物(长石、石英)微裂隙及粒间分布的非结构铀。对富城花岗岩铀配分研究发现,赋存在造岩矿物中均匀分散状的结构铀含量与全岩铀不呈消长关系,而是存在一定的极限值:长石、石英<3×1-0 6,白云母<5×10-6,黑云母<9×10-6。溶浸实验结果表明,富城花岗岩活动性铀浸出率很高(平均值52%),为富城花岗岩具有较大铀成矿潜力提供了佐证。 相似文献
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三种微生物对铀的吸附行为研究 总被引:1,自引:0,他引:1
开展了酵母菌(真菌)、枯草芽孢杆菌(细菌)、小球藻(藻类)对水体中铀(Ⅵ)的吸附性能及机理研究.结果表明:3种微生物对铀都具有较好的吸附效果.酵母菌,小球藻,枯草芽孢杆菌对铀的最佳吸附率分别为97.19%、97.13%、98.03%;且最大吸附量分别达到341.2、356.5、512.5mgU/g(DW).3种微生物对铀的吸附过程和机理有所不同,酵母菌和小球藻符合Langmuir模型,枯草芽孢杆菌更适合Freundlich模型,吸附至12h,酵母菌表面逐渐出现铀和磷的片状结晶及含铀沉积物堆积,小球藻和枯草芽孢杆菌与铀(50mgU/L)作用后细胞出现明显变形,菌体表面未出现铀的结晶物. 相似文献
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Mary Beth LEIGH Wei-Min WU Erick CARDENAS Ondrej UHLIK Sue CARROLL Terry GENTRY Terence L. MARSH Jizhong ZHOU Philip JARDINE Craig S. CRIDDLE James M. TIEDJE 《Frontiers of Environmental Science & Engineering》2015,9(3):453
Stable isotope probing (SIP) was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with 13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24 h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosm with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U(VI) reduction in the less reduced sample. 13C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron (III) reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U(VI)-reducing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobacter and Desulfosporosinus. The findings suggest that ethanol biostimulates the U(VI)-reducing microbial community by first serving as an electron donor for nitrate, sulfate, iron (III) and U(VI) reduction, and acetate which then functions as electron donor for U(VI) reduction and carbon source for microbial growth. 相似文献