Long‐Term Dynamics of a Fragmented Rainforest Mammal Assemblage

Abstract: Habitat fragmentation is a severe threat to tropical biotas, but its long‐term effects are poorly understood. We evaluated longer‐term changes in the abundance of larger (>1 kg) mammals in fragmented and intact rainforest and in riparian “corridors” in tropical Queensland, with data from 190 spotlighting surveys conducted in 1986–1987 and 2006–2007. In 1986–1987 when most fragments were already 20–50 years old, mammal assemblages differed markedly between fragmented and intact forest. Most vulnerable were lemuroid ringtail possums (Hemibelideus lemuroides), followed by Lumholtz's tree‐kangaroos (Dendrolagus lumholtzi) and Herbert River ringtail possums (Pseudocheirus herbertensis). Further changes were evident 20 years later. Mammal species richness fell significantly in fragments, and the abundances of 4 species, coppery brushtail possums (Trichosurus vulpecula johnstoni), green ringtail possums (Pseudochirops archeri), red‐legged pademelons (Thylogale stigmatica), and tree‐kangaroos, declined significantly. The most surprising finding was that the lemuroid ringtail, a strict rainforest specialist, apparently recolonized one fragment, despite a 99.98% decrease in abundance in fragments and corridors. A combination of factors, including long‐term fragmentation effects, shifts in the surrounding matrix vegetation, and recurring cyclone disturbances, appear to underlie these dynamic changes in mammal assemblages.     

丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯的合成与螯合性能研究

用2,3-二羟基苯甲酸经羟基保护、酰胺化、酯化和去保护4步反应,生成一种新型的四齿丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯配体.采用傅里叶变换红外光谱(FT-IR)、紫外-可见光谱(UV-Vis)、核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)和质谱(MS)对其结构进行了表征.在中性pH值条件下,研究了这种配体对铀酰离子的络合能力.结果表明,丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯配体与铀酰离子的螯合常数为23.2.     

北京夏季典型PM2.5与O3相继重污染事件分析

根据北京市环境保护监测中心发布的PM2.5和O3小时质量浓度及气象、卫星遥感数据,分析了2013年7月2日至10日北京典型PM2.5及O3重污染过程的质量浓度特征及在大气边界层过程各个阶段的质量浓度演变.结果表明,北京夏季O3质量浓度先于PM2.5达到峰值,而天气型演变是导致这一现象的主要原因.具体过程为:1)重污染初始阶段,高压天气型利于前体物积累,PM2.5及O3质量浓度升高;2)在反气旋中部,由于各种污染物质量浓度较低,对大气紫外波段辐射的吸收较弱,导致该阶段紫外辐射强,因而加快了O3生成的光化学反应,O3质量浓度最先达到峰值;3)在反气旋后部,随PM2.5质量浓度增加,辐射变弱,因此O3质量浓度增加速度下降,而受高压后部影响,区域内PM2.5经东南风输送通道进入北京,导致北京PM2.5质量浓度相继达到峰值;4)在重污染清除阶段,在北方反气旋前部的冷锋清除作用下,PM2.5及O3质量浓度同时降低至谷值.     

三江平原泥炭沼泽孔隙水甲烷浓度变化动态及其影响因子

湿地土壤孔隙水甲烷浓度变化动态对于揭示湿地碳循环过程具有重要作用.于2012年和2013年对三江平原毛苔草泥炭沼泽不同土壤深度孔隙水甲烷浓度的季节变化动态进行监测,并分析了其关键影响因子.结果表明:植物生长季孔隙水甲烷浓度呈单峰变化趋势,不同土层甲烷浓度峰值(80.45~490.95μmol·L-1)主要集中在湿润的生长季末,但年际间存在显著差异;从土壤剖面来看,土壤融通之后,孔隙水中甲烷浓度随着土壤深度的增加而增加;土壤表层(5 cm和10 cm)甲烷浓度主要受到株高(R2=0.6,p=0.005)和土壤充水孔隙率(R2=0.36,p=0.01)的影响,而深层(20~40 cm)甲烷浓度主要受到土壤温度等因素的综合影响.研究还表明,表层土壤孔隙水甲烷浓度能够解释生长季甲烷排放通量变化的26%~60%,而且短期的极端降雨事件可能不会对甲烷浓度以及甲烷排放产生即时影响,而是出现大约一周的延迟(time lag)现象,这主要取决于实际土壤湿度.     

甲烷氧化菌在填埋场覆盖层中的工程应用(Ⅱ):基质选择性及长效性

针对已筛选获得的甲烷氧化混合菌,选取填埋场覆盖土(LCS)、矿化垃圾(AR)和塘渣(TZ)3种填埋场周边易得的材料为供试生存基质,从基质选择性及长效性角度进行了甲烷减排应用条件的探究及使用效能评估.结果表明,在TZ、LCS、AR、TZ-AR和LCS-AR这5种生存基质中,TZ-AR最适合甲烷氧化混合菌的生长,且TZ与AR的复配比例以5∶5为最佳.甲烷氧化混合菌在TZ-AR的粒径≤4 mm和含水率为20%时具有最高甲烷氧化能力.一次性接种甲烷氧化混合菌在静态体系中的最佳使用有效期为31 d.其在接种量为0.08、0.16、0.20 m L·g-1和0.25m L·g-1时甲烷氧化速率无明显差异,从工程应用角度而言,8%的接种量为最佳.     

管道中烟道气流动传热及酸凝结规律

针对注烟道气稠油热采中管道输送烟道气酸凝结问题,以连续性方程、能量方程和动量方程为基础建立了烟道气沿管道流动与传热计算模型,计算了烟道气沿管道的压力分布、温度分布和酸凝结点距离,分析了不同入口参数和烟道气成分对管道中烟道气的压力、温度、酸凝结点的影响。结果表明:SO3或水蒸汽含量增加时,烟道气酸凝结点温度提高,凝结点距离减小;入口烟道气压力提高,烟道气压降变小,温降不变,酸凝结点距离减小;入口烟温升高,压降和温降都增大,酸凝结点距离增大;保温层厚度增加,温降减小,酸凝结点距离增大。计算和分析结果表明:减少烟道气中SO3或水蒸汽含量可以有效地增大酸凝结点距离,减轻管道腐蚀问题。     

Acid-assisted hydrothermal synthesis of nanocrystalline TiO2 from titanate nanotubes: Influence of acids on the photodegradation of gaseous toluene

In order to efficiently remove volatile organic compounds (VOCs) from indoor air, onedimensional titanate nanotubes (TiNTs) were hydrothermally treated to prepare TiO₂ nanocrystals with different crystalline phases, shapes and sizes. The influences of various acids such as CH₃COOH, HNO₃, HCl, HF and H₂SO₄ used in the treatment were separately compared to optimize the performance of the TiO₂ nanocrystals. Comparedwith the strong and corrosive inorganic acids, CH₃COOH was not only safer andmore environmentally friendly, but also more efficient in promoting the photocatalytic activity of the obtained TiO₂. Itwasobserved that the anatase TiO₂ synthesized in 15 mol/L CH₃COOH solution exhibited the highest photodegradation rate of gaseous toluene (94%), exceeding that of P25 (44%) by a factor ofmore than two. The improved photocatalytic activity was attributed to the small crystallite size and surface modification by CH₃COOH. The influence of relative humidity (20%-80%) on the performance of TiO₂ nanocrystals was also studied. The anatase TiO₂ synthesized in 15 mol/L CH₃COOH solution was more tolerant tomoisture than the other TiO₂ nanocrystals and P25.     

Synthesis, crystal structure, photodegradation kinetics and photocatalytic activity of novel photocatalyst ZnBiYO4

ZnBiYO₄ was synthesized by a solid-state reaction method for the first time. The structural and photocatalytic properties of ZnBiYO₄ were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Vis diffuse reflectance. ZnBiYO₄ crystallized with a tetragonal spinel structure with space group I41/A. The lattice parameters for ZnBiYO₄ were a = b = 11.176479 Å and c= 10.014323 Å. The band gap of ZnBiYO₄ was estimated to be 1.58 eV. The photocatalytic activity of ZnBiYO₄ was assessed by photodegradation of methyl orange under visible light irradiation. The results showed that ZnBiYO₄ had higher catalytic activity compared with N-doped TiO₂ under the same experimental conditions using visible light irradiation. The photocatalytic degradation of methyl orange with ZnBiYO₄ or N-doped TiO₂ as catalyst followed first-order reaction kinetics, and the first-order rate constant was 0.01575 and 0.00416 min^-1 for ZnBiYO₄ and N-doped TiO₂, respectively. After visible light irradiation for 220 min with ZnBiYO₄ as catalyst, complete removal and mineralization of methyl orange were observed. The reduction of total organic carbon, formation of inorganic products, SO₄^2- and NO₃^-, and evolution of CO₂ revealed the continuous mineralization of methyl orange during the photocatalytic process. The intermediate products were identified using liquid chromatography- mass spectrometry. The ZnBiYO₄/(visible light) photocatalysis system was found to be suitable for textile industry wastewater treatment and could be used to solve other environmental chemical pollution problems.     

Diurnal and spatial variations of soil NOx fluxes in the northern steppe of China

NO_x emissions from biogenic sources in soils play a significant role in the gaseous loss of soil nitrogen and consequent changes in tropospheric chemistry. In order to investigate the characteristics of NO_x fluxes and factors influencing these fluxes in degraded sandy grasslands in northern China, diurnal and spatial variations of NO_x fluxes were measured in situ. A dynamic flux chamber method was used at eight sites with various vegetation coverages and soil types in the northern steppe of China in the summer season of 2010. Fluxes of NO_x from soils with plant covers were generally higher than those in the corresponding bare vegetation-free soils, indicating that the canopy plays an important role in the exchange of NO_x between soil and air. The fluxes of NO_x increased in the daytime, and decreased during the nighttime, with peak emissions occurring between 12:00 and 14:00. The results of multiple linear regression analysis indicated that the diurnal variation of NO_x fluxes was positively correlated with soil temperature (P < 0.05) and negatively with soil moisture content (P < 0.05). Based on measurement over a season, the overall variation in NO_x flux was lower than that of soil nitrogen contents, suggesting that the gaseous loss of N fromthe grasslands of northern China was not a significant contributor to the high C/N in the northern steppe of China. The concentration of NO_x emitted from soils in the region did not exceed the 1-hr National Ambient Air Quality Standard (0.25 mg/m³).