大型水母爆发对东海生态系统中上层能量平衡的影响

通过建立东海生态系统ECOPATH模型,并将大型水母作为一个独立的功能组,从能量平衡的角度探讨近年来东海大型水母爆发对生态系统的影响,并在此基础上提出抑制大型水母爆发加剧的控制机制的假说。模型分析结果表明:大型水母对中上层生物资源普遍具有显著不利影响;在大型水母、浮游动物和鲳鱼等小型中上层鱼类之间可能存在一个由大型水母爆发引发的生态系统中上层能量反馈循环;大型水母爆发初期将破坏生态系统中上层能量平衡;浮游动物生物量的波动可能是抑制大型水母爆发加剧的自然控制机制之一。     

苯胺装置火灾爆炸事故的多米诺效应分析

针对一次苯胺装置重大火灾爆炸事故发生经过,分析了其多米诺效应发生的机理,找出了事故扩大的升级因素,计算了相应的多米诺效应破坏概率,并提出了预防事故多米诺效应的安全对策和相应的措施.     

空气中臭氧变化特征分析

利用空气自动监测子站中O3自动监测分析仪,对2007年2月－2008年2月鞍山深沟寺地区进行24小时连续监测,利用连续监测的数据,研究了空气中臭氧全年总体分布、季节变化、日变化规律。结果表明,本地区φ（O3）全年平均值为0．068mg／m^3,φ（O3）月均值在春末夏初季节出现达到最大值,在11月一次年1月出现低值,说明鞍山地区夏季臭氧光化学反应比较强烈。φ（O3）浓度随季节变化明显,春末夏初随日照时间加长而增高,最大月均值和最大日均值均出现在此时期,冬季随日照时间的减短而降低。     

环境有效微生物菌剂治理蓝藻水华研究

在北京市延庆县妫水现场围隔水体中,通过投加由芽孢杆菌、酵母菌、乳酸菌、放线菌和沼泽红假单胞菌组成的环境有效微生物菌剂(EM菌剂)治理蓝藻水华污染的效果进行了研究。实验结果表明:与对照相比,投加EM菌剂不仅可以快速降低蓝藻数量,使蓝藻生物量减少55%以上,而且能够迅速降低水体中的氨氮、亚硝酸氮、总氮和磷酸盐浓度并维持在较低水平波动,从而降低了形成蓝藻水华所需要的氮和磷营养元素,因此控制了蓝藻水华的发展,具有重要的应用价值。     

Overstorey tree density and understorey regrowth effects on plant composition,stand structure and floristic richness in grazed temperate woodlands in eastern Australia

As natural woodlands decline in both extent and quality worldwide, there is an increasing recognition of the biodiversity conservation value of production landscapes. In low-input, low-productivity grazing systems in Australia, the modification of natural woodlands through overstorey tree and woody regrowth removal are vegetation management options used by landholders to increase native grass production for livestock grazing; however, there is little empirical evidence to indicate at what tree densities biodiversity attributes are compromised. We examined the effects of overstorey tree density and understorey regowth on the floristic composition, stand structure and species richness of eucalypt woodlands in a grazing landscape in the Traprock region of southern Queensland, Australia. We sampled 47 sites stratified according to vegetation type (Eucalyptus crebra/Eucalyptus dealbata woodland; Eucalyptus melliodora/Eucalyptus microcarpa grassy woodland), density of mature trees (<6 trees/ha; 6–20 trees/ha; >20 trees/ha), and presence/absence of regrowth. Distinct patterns in composition were detected using indicator species analysis and non-metric multidimensional scaling, with low density areas compositionally indistinguishable, although distinct from other land management units. Within vegetation type, medium tree density woodlands were compositionally similar to high density and reference woodlands. Species richness ranged from 18 to 67 species per 500 m² across all sites. No differences in total or native species richness were detected across management units; however, some differences in exotic species richness were detected. Differences in grass cover existed between low and high density management units, yet no difference in grass cover was evident between low and medium density management units. Our results suggest that medium tree densities may provide biodiversity benefits concordant with more natural areas, yet not adversely impact on pasture production. Retaining trees in grazing landscapes provides significant landscape heterogeneity and important refuges for species that may be largely excluded from open grassland habitats. Maintaining a medium density of overstorey trees in grazed paddocks can provide both production and biodiversity benefits.     

城市功能对贵阳市城区土壤重金属分布的影响

将贵阳市城区土壤按照不同功能区取样分析,研究贵阳市城区多种土地利用功能下土壤重金属累积(污染)程度及分异特征。结果表明:贵阳市城区校园土壤As(21.8mg/kg)、Ni(47.1mg/kg)和Pb(139mg/kg)含量最高,工业区土壤Cd(1.48mg/kg)和Zn(314mg/kg)含量最高,垃圾中转站土壤Cu(115mg/kg)含量最高,工业区、学校、垃圾中转站和交通十字路口土壤重金属累积较重,并已达到轻度污染,住宅、公园和广场土壤重金属累积程度较轻,处于清洁水平。工业区土壤主要污染金属为Cd、Zn和Pb,学校、交通路口土壤主要污染元素是Pb和Cd,垃圾中转站土壤主要污染元素是Cd和Zn。贵阳市城区土壤Cd、Zn和Pb受人类活动影响较大,其中土地利用功能导致贵阳市城区土壤Pb的分异程度最大。     

凤眼莲对富营养化水体硝化、反硝化脱氮释放N2O的影响

以往有关大型水生漂浮植物消减富营养化水体氮(N)的研究主要侧重于植物对N的吸收效果,而忽略了硝化、反硝化反应途径对水体脱氮的贡献.基于此,本研究中借助具创新性的收集凤眼莲种植水体释放N₂O的装置和方法,通过模拟实验研究了凤眼莲对富营养化水体硝化、反硝化脱氮中间产物N₂O的影响.结果表明,凤眼莲可以促进富营养化水体的硝化、反硝化、成对硝化-反硝化反应过程,在本实验条件下凤眼莲种植水体在整个培养期内释放的N₂O气体浓度累积升高幅度较大,为453~4055 nL·L^-1(未加硝化抑制剂处理),通过释放N₂O而脱除氮素的量占整个水体N消减量的1.36%,为相应未种植凤眼莲水体的4.31倍.种植凤眼莲水体试验期间释放N₂O-N的量与水体氨态氮或硝态氮浓度的变化量均存在显著相关关系(p<0.05),说明N₂O释放量受到水体中NH₄⁺、NO₃^-浓度变化的影响.种植凤眼莲在实验中后期可以增加水体中硝化、反硝化细菌的数量,但其数量远低于凤眼莲根系附着的硝化反硝化细菌.水体中反硝化细菌数量与水体释放N₂O浓度之间并无显著相关性,说明种植凤眼莲水体反硝化脱氮释放N₂O过程可能主要是由根系共生微生物驱动的.     

液液萃取-高效液相色谱法同时测定饮用水中阿特拉津与甲萘威

通过液液萃取-高效液相色谱法实现了饮用水中农药残留阿特拉津与甲萘威的同时测定。用二氯甲烷萃取水样中阿特拉津与甲萘威,浓缩定容后,以甲醇∶水=60∶40(体积分数)为流动相,用Zorbax SB-C18柱进行分离,通过具有紫外检测器的高效液相色谱仪进行测定。阿特拉津与甲萘威的最低检出限均可达0.000 1 mg/L,加标量为1 ug时平均回收率分别为85.45%和83.35%,加标量为0.1 ug时平均回收率分别为81.09%和80.23%。平行7次进行精密度试验,相对标准差在4.10%～4.59%。结果表明:方法简便、准确、快速、重现性好,适合饮用水中阿特拉津与甲萘威的同时测定。     

Study on methane conversion to syngas over nano Pt-CeO2-ZrO2/MgO catalysts: Structure and catalytic behavior of catalysts prepared by using ion exchange resin method

Nano Pt-Ce0₂-Zr0₂/MgO catalysts with 0.8 wt.% Pt, 3.0 wt.% Ce0₂ and 3.0 wt.% Zr0₂ were prepared by wet impregnation mothod. Support MgO was obtained using ion exchange resin method or using commercial MgO. S_BET, XRD, TEM and C0₂-TPD were used to characterize the supports and catalysts. CH₄-C0₂ reforming to synthesis gas was performed to test the catalytic behavior of the catalysts. The catalysts prepared using ion exchange resin exhibited more regular structure, more basic sites and higher stability of Pt and MgO than prepared from commercial MgO. At 1073 K, atmospheric pressure, and at high gas hourly space velocity of 36,000 mL/(g-hr) with a stoichiometric feed of CH₄ and C0₂, the catalyst supported on the MOH(GD)-IE showed a higher and more stable activity for CH₄-C0₂ reforming reaction than the catalyst prepared using commercial MgO. The characterisation results demonstrated that the high activity and stability of the catalyst stem from the high dispersion of Pt, the stable structure and the high resistance to carbon deposition on the catalyst.     

我国硒污染分析与电解锰行业控制对策

硒是生命活动中的重要元素,世界卫生组织(WHO)1973年确认硒是人类生命必须14种微量元素中的第一线微量元素。硒的营养与中毒的界限是所有元素中最小的一个,若不足,则生物效应为"存活,缺乏",若过量,则"毒性,致死"。为了有效提高电解锰生产过程中的电流效率,国内企业广泛使用二氧化硒(SeO2)作为添加剂,导致操作工人长期暴露在硒污染作业环境中,同时锰渣中挟带大量的硒污染物进入到外环境中,存在着严重而明显的环境和生态隐患。因此,研究分析电解锰行业硒污染及其控制技术具有其必要性及重要性。