Distribution and Variation of Ribonucleic Acid （RNA） and Protein and Its Hydrolysis Products in Lake Sediments

Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition —amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein. The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities. The research project was financially supported jointly by the Ntional Natural Science Foundation of China (No. 40173038) and the Guizhou Provincial Foundation (No. 3090) and the Chinese Academy of Sciences Knowledge-Innovation Foundation (KZCX2-105).     

酸法地浸采铀中信息参数的判断及其应用

介绍了酸法地浸采铀工艺信息技术的显示,在长期生产和科研实践的基础上,总结归纳了酸法地浸采铀工艺的基本信息技术,以及如何利用这些信息对地浸开采实现有效的判断和调控,这些内容是地浸工作者必备和需要掌握的重要开采技术和手段。     

Influence of basin characteristics on baseflow and stormflow chemistry in the Great Smoky Mountains National Park,USA

Relationships between stream chemistry and elevation, area, Anakeesta geology, soil properties, and dominant vegetation were evaluated to identify the influence of basin characteristics on baseflow and stormflow chemistry in eight streams of the Great Smoky Mountains National Park. Statistical analyses were employed to determine differences between baseflow and stormflow chemistry, and relate basin‐scale factors governing local chemical processes to stream chemistry. Following precipitation events, stream pH was reduced and aluminium concentrations increased, while the response of acid neutralizing capacity (ANC), nitrate, sulfate, and base cations varied. Several basin characteristics were highly correlated with each other, demonstrating the interrelatedness of topographical, geological, soil, and vegetative parameters. These interrelated basin factors uniquely influenced acidification response in these streams. Streams in higher‐elevation basins (>975 m) had significantly lower pH, ANC, sodium, and silicon and higher nitrate concentrations (p < 0.05). Streams in smaller basins (<10 km²) had significantly lower nitrate, sodium, magnesium, silicon, and base cation concentrations. In stormflow, streams in basins with Anakeesta geology (>10%) had significantly lower pH and sodium concentrations, and higher aluminium concentrations. Chemical and physical soil characteristics and dominant overstory vegetation in basins were more strongly correlated with baseflow and stormflow chemical constituents than topographical and geological basin factors. Saturated hydraulic conductivity, of all the soil parameters, was most related to concentrations of stormflow constituents. Basins with higher average hydraulic conductivities were associated with lower stream pH, ANC, and base cation concentrations, and higher nitrate and sulfate concentrations. These results emphasize the importance of soil and geological properties influencing stream chemistry and promote the prioritization of management strategies for aquatic resources. Copyright © 2012 John Wiley & Sons, Ltd.     

桂林典型岩溶区和非岩溶区土壤剖面钙镁形态迁移对比

文章以桂林典型岩溶区和非岩溶区土壤剖面为研究对象,采用改进的Tessier元素形态连续提取法,测定岩溶区和非岩溶区土壤钙（Ca）和镁（Mg）元素离子交换态（包括水溶态）、碳酸盐结合态、腐殖酸结合态、铁锰氧化物结合态、强有机质结合态（包括部分硫化物）和残渣态等形态,探讨岩溶区和非岩溶区土壤Ca、Mg形态在土壤剖面中的迁移变化特征。结果表明：（1）岩溶区石灰土剖面中,随剖面深度加深,pH值增大,而土壤有机质、全氮（N）、全磷（P）含量减少,Ca元素主要以交换态存在且在各土壤剖面中含量相近,Mg元素主要是以残渣态赋存在土壤剖面中,随着土壤剖面深度腐殖酸结合态百分比减少,存在累积现象;（2）在非岩溶地区酸性土壤中,土壤总钙较低。在土壤剖面0~60 cm以强有机结合态为主,深层剖面（大于60 cm）以残渣态为主;Mg元素有效态含量较低,非岩溶区土壤Mg元素以腐殖酸结合态和残渣态为主,与岩溶区土壤类似,非岩溶区Mg元素在土壤中也存在一定累积。     

酸性金黄染料在即时合成层状双氢氧化物结构中嵌入作用

工业染料废水是一类治理难度很大的有机废水,研究新的处理工业染料废水的方法是水污染控制技术领域的重要课题之一。本文研究即时合成层状双氢氧化物(LDH)处理酸性金黄溶液的效果以及影响因素,并利用XRD分析研究了酸性金黄染料在LDH结构中的嵌入方式和反应机理。结果表明,在酸性金黄溶液中同时加入镁盐和铝盐,在pH 7~11的范围内,酸性金黄都有很高的去除率。酸性金黄阴离子以补偿LDH层板电荷的形式嵌入到层间。嵌入到层间的酸性金黄阴离子以双层倾斜45°方式排列。     

运用吡啶吸附—拉曼光谱探测硅藻土表面酸位

运用吡啶吸附—拉曼光谱技术探测了硅藻土及其热处理产物的表面固体酸位。结果表明，室温下硅藻土表面经基均为吸附水覆盖，不显B酸性，结构中也无能够接受电子对的Lewis酸位。经热处理后，某些酸性羟基脱水使硅藻土呈弱B酸性，B酸位浓度在经650℃左右热处理后达到最大；另一方面，硅藻土中所含粘土矿物在650℃左右因脱羟而发生结构变化，产生配位不饱和的Al位，表现出L酸性。     

改性层状粘土矿物固体酸酸强度及其催化性能研究

用盐酸对高岭石和蒙脱石进行酸活化改性,再对酸活化后的蒙脱石进行羟基铝柱撑改性,然后采用X射线衍射仪对改性前后的矿物结构进行表征,并在此基础上,采用Hammett指示剂法,以正丁胺-环己烷滴定在H0为+4. 8～-5. 6酸强度范围的固体表面酸上,测出各粘土在不同酸强度下的酸量,拟合得到其酸强度分布曲线,最后以异丙苯裂解转化为模型考察了各粘土固体酸的催化性能。实验结果表明,高岭石和蒙脱石经酸活化后虽然可以提高异丙苯转化率,但是催化稳定性却有所降低;蒙脱石经过羟基铝柱撑改性后不仅大幅度提高了异丙苯转化率,而且还提高了催化稳定性。     

外源ASA对菹草(Potamogeton crispus)抗Cd2+毒害的实验分析

实验以高等水生沉水植物菹草为材料,研究在不同浓度Cd^2 毒害条件下外施乙酰水杨酸(ASA)对菹草叶中叶绿素含量、可容性蛋白含量、O2^v产生速率、保护酶——超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响结果表明,施用ASA可以显著提高叶绿素和可溶性蛋白的含量,增强保护酶的活性,降低O2^v产生速率、从而减轻了重金属Cd^2 胁迫对植物体造成的伤害．     

不同含水率条件下土壤中赤霉酸自然衰减规律研究

作为一种施用范围广、用量大的微毒农药,赤霉酸（GA3）的高溶解度会造成其在土壤中的弱吸附和强迁移并伴随强烈的自然衰减,且受到间歇性灌溉过程中变化土壤含水率的影响,因此有必要系统研究不同含水率条件下土壤中GA3的自然衰减规律。通过设置10%、20%、30%的3种土壤含水率,研究了不同土壤含水率条件下GA3的自然衰减规律,分析了土壤微生物对GA3自然衰减过程的影响,定性识别了GA3自然衰减产物。结果表明：（1）实验结束（34 d）时初始含水率为10%、20%和30%的灭菌组和未灭菌组土壤中GA3的自然衰减率分别为87.77%、89.70%、90.70%和87.70%、94.47%、95.87%,其自然衰减半衰期分别为12.38,12.16,12.60 d和8.56,6.80,7.07 d;（2）含水率对灭菌组土壤GA3的自然衰减速率无显著影响,未灭菌组在不同土壤含水率条件下GA3自然衰减速率有差异（20%土壤含水率最大）;（3）在水解作用的基础上,土壤微生物降解进一步促进了GA3的自然衰减,且生物降解贡献率为39.62%±7.58%;（4）GA3主要自然衰减产物为异构赤霉酸与赤霉烯酸（其中异构赤霉酸占比更大）,未来需要进一步关注GA3自然衰减产物在环境中的生物毒性与环境风险。上述研究结果有助于进一步深入理解农业生产过程土壤中GA3的环境行为,并为其环境毒性及潜在风险评估与管控提供数据支撑。     

硅限制对三角褐指藻叶绿素a、叶黄素含量和脂肪酸组成的影响

为研究硅限制对三角褐指藻脂肪酸组成的影响,用不含硅的f/2人工海水培养基对处于生长指数末期的三角褐指藻进行了0、6、12、24、48h的硅限制并测定了其叶绿素a、叶黄素含量和脂肪酸组成。结果表明,硅限制对三角褐指藻叶绿素a和叶黄素含量无影响,对脂肪酸组成影响显著。硅限制显著增加了C14∶0、C16∶0、C16∶1、C16∶2、C20∶5(EPA)百分含量,但各脂肪酸响应硅限制的时间不同。C14∶0在硅限制24、48h显著增加,分别是对照组的1.33倍、1.41倍。C16∶0在硅限制6、48h显著增加,分别是对照组的1.12倍、1.19倍;C16∶1在硅限制48h显著增加,是对照组的1.16倍;C16∶2在硅限制24h显著高于对照组,是对照组的1.27倍;EPA在硅限制24h百分含量达到最大值21.86%,分别是0h和对照组的1.11倍、1.18倍。研究结果表明,一定时间的硅限制能显著提高三角褐指藻EPA百分含量,以期为工业化生产EPA提供理论参考。