载钛活性炭纤维的制备及其对水中罗丹明B的光催化降解

通过溶胶凝胶法制备载钛活性炭纤维(TiO2-ACF)复合材料,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见吸收(UV-Vis)、傅里叶红外分光光度计(FT-IR)、X射线光电子能谱(XPS)对TiO2-ACF进行了表征,并研究了TiO2-ACF对水中罗丹明B的光催化性能.结果表明,煅烧温度为400—600℃时,负载在ACF上的TiO2为锐钛矿型,当煅烧温度上升到700℃时,TiO2开始出现金红石型,600℃时煅烧制备的TiO2-ACF对水中罗丹明B的降解效果最佳;TiO2-ACF对罗丹明B的吸附能力比ACF低;但是在紫外光条件下,60 min后TiO2-ACF对罗丹明B的降解率比ACF、TiO2对罗丹明B的降解率分别高8.6%和16.2%,TiO2-ACF表现出较高的光催化活性.     

转Cry1Ac基因抗虫棉与其亲本棉花根际真菌多样性的比较

在温室条件下,利用PCR-DGGE技术和Q-PCR技术分析了两种转Cry1Ac基因抗虫棉及其亲本棉花在不同取样时期的根际真菌多样性和生物量的动态变化情况,以评价其生态安全.结果表明,转Bt基因棉与对照棉根际真菌优势条带组成在不同的取样时期极为相似,三者间差异条带多为不清晰的条带.转Bt棉SGK321根际真菌的生物量在苗期明显低于亲本对照,转Bt棉XP188根际真菌的生物量在花铃期较对照有轻微降低,其它时期两种转Bt棉根际真菌生物量没有显著降低,甚至还有增加的趋势.不过根际真菌群落结构的改变和生物量的差异不仅存在于转基因棉和其亲本对照棉之间,它同样存在于对照棉SHIYUAN321和JM20之间以及转基因棉SGK321和XP188之间.可见Bt并不是造成转基因棉和非转基因棉根际真菌群落结构差异、多样性改变和生物量减少的唯一诱因,品种的不同也对它们也有影响.     

Pseudomonas sp. QJX-1的锰氧化特性研究

从锰矿土壤样品中分离、纯化出1株高效锰氧化细菌(QJX-1),经16S rDNA序列鉴定为Pseudomonas sp.QJX-1.研究表明,Pseudomonas sp.QJX-1含有锰氧化的必需成分多铜氧化酶基因CumA,当初始Mn2+为5.05 mg·L-1,菌密度D600为0.020时,该菌可在48 h内将Mn2+转化,且转化率高达99.4%.在寡营养条件下该菌锰氧化速率较富营养条件下有显著提高;添加石英砂滤料促使生物膜的快速形成,进而促进Mn2+的生物转化.根据研究结果推测地下水处理过程中生物锰氧化速率较快.     

黄曲霉A5p1脱色类黑精及其机理初探:葡萄糖氧化酶的作用

类黑精是一种高分子难降解色素污染物质,在糖蜜酒精废水中大量存在.选取在前期研究中对糖蜜酒精废水具有较好脱色作用的黄曲霉(Aspergillus flavus)A5p1(保藏号CGMCC.4292),以合成的类黑精为对象研究脱色机理,试图为实际废水的生物脱色提供理论基础.结果显示,此菌株对合成类黑精具有生物吸附和生物降解的双重作用,以后者为主,最高脱色率可达65%.相较于漆酶、依赖/不依赖于锰的过氧化物酶等常规氧化脱色酶,此菌株中的产过氧化氢酶对脱色起主要作用,而且脱色过程中作为产过氧化氢酶之一的葡萄糖氧化酶与类黑精脱色率之间存在着一定的正相关性.添加葡萄糖氧化酶激活剂和抑制剂进行验证,发现葡萄糖氧化酶酶活力、过氧化氢产量和脱色率三者之间呈相关性变化.初步推测,葡萄糖氧化酶是黄曲霉A5p1生物降解脱色类黑精的关键酶之一.     

Evaluation of Bacillus sp. MZS10 for decolorizing Azure B dye and its decolorization mechanism

To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55%(0.04 g/L) after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy(UPLC-MS). A mechanism for decolorization of Azure B was proposed as follows: the C=N in Azure B was initially reduced to –NH by nicotinamide adenine dinucleotide phosphate(NADPH)-dependent quinone dehydrogenase, and then the –NH further combined with –OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.     

Isomeric analysis of PCDD/PCDF in waste incinerator fly ash by GC-MS/MS

The development of an analytical method for the analysis of PCDD/PCDF in flyash using a bench analytical system comprising of a gas chromatograph fitted with an ion trap detector operated in the tandem MS mode is described. The optimum settings for the most important MS/MS parameters are given, including those for the less reported mono- to tri-chlorinated dioxin and furan congener groups. Flyash samples from three waste incineration plants representing a decommissioned 1970s plant design, an upgraded and still operating plant originally designed in the 1970s, and a modern 1990s design operating plant have been analysed for PCDD/PCDF. The flyash samples were analysed for PCDD/PCDF using the methods developed and the total PCDD/PCDF, I-TEQ values and isomeric profiles are reported. The flyash from the older decommissioned incinerator had very significantly higher concentrations of PCDD/PCDF compared to the modern incinerator flyash.     

聚丙烯腈基活性炭纤维对罗丹明B吸附性能研究

利用扫描电子显微镜（SEM）和比表面分析仪等对聚丙烯腈基活性炭纤维进行表征。考察了吸附动力学、pH值、吸附温度及罗丹明B初始浓度对吸附性能的影响。结果表明,最佳接触时间为140min;在中性条件下,罗丹明B的去除率最低,pH=2.0时达到最大;温度为55℃时,ACFs的吸附效果最好;罗丹明B的去除率随着罗丹明B初始浓度增大而减小。并对材料的吸附机制进行了简要的分析。     

Prioritizing Conservation Effort through the Use of Biological Soil Crusts as Ecosystem Function Indicators in an Arid Region

Abstract: Conservation prioritization usually focuses on conservation of rare species or biodiversity, rather than ecological processes. This is partially due to a lack of informative indicators of ecosystem function. Biological soil crusts (BSCs) trap and retain soil and water resources in arid ecosystems and function as major carbon and nitrogen fixers; thus, they may be informative indicators of ecosystem function. We created spatial models of multiple indicators of the diversity and function of BSCs (species richness, evenness, functional diversity, functional redundancy, number of rare species, number of habitat specialists, nitrogen and carbon fixation indices, soil stabilization, and surface roughening) for the 800,000‐ha Grand Staircase‐Escalante National Monument (Utah, U.S.A.). We then combined the indicators into a single BSC function map and a single BSC biodiversity map (2 alternative types of conservation value) with an unweighted averaging procedure and a weighted procedure derived from validations performance. We also modeled potential degradation with data from a rangeland assessment survey. To determine which areas on the landscape were the highest conservation priorities, we overlaid the function‐ and diversity‐based conservation‐value layers on the potential degradation layer. Different methods for ascribing conservation‐value and conservation‐priority layers all yielded strikingly similar results (r= 0.89–0.99), which suggests that in this case biodiversity and function can be conserved simultaneously. We believe BSCs can be used as indicators of ecosystem function in concert with other indicators (such as plant‐community properties) and that such information can be used to prioritize conservation effort in drylands.     

Quantifying Loss of Acoustic Communication Space for Right Whales in and around a U.S. National Marine Sanctuary

The effects of chronic exposure to increasing levels of human‐induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human‐induced sound on contact‐calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (～10,000 km²) and time period (peak feeding time). We used an array of temporary, bottom‐mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel‐tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal‐to‐noise ratio and the assumed recognition differential) for contact‐calling right whales was negative (?1 dB) under current ambient noise levels and was further reduced (?2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10‐min period. These results highlight the limitations of exposure‐threshold (i.e., dose‐response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide‐ranging noise effects in emerging ocean‐planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A.