湖南省绥宁县黄桑坪自然保护区珍稀濒危植物长苞铁杉自然种群年龄结构及生态对策

通过对湖南省绥宁县黄桑坪自然保护区长苞铁杉的种群结构、特定时间生命表、生殖价分析、分布数量与环境因子的关系进行分析.结果表明:(1)种群结构数量具有"中间大,两头小"的特点,为衰退型种群,虽然种群有一定的幼龄个体,但死亡率高,35 a内长苞铁杉的年龄结构模型为:Age(a)=0.002 765(DBH)3-0.128 756(DBH)2+4.120 978(DBH)+13.439 846(R=0.991 2,F=2 654.48);(2)长苞铁杉种群既有r对策特征,又有K对策特征,该种群处于r对策→K对策的过渡阶段;(3)长苞铁杉的累积剩余生殖价(SRRV)和整个生活史的总生殖价(TRV)呈现出逐渐递减的趋势,而生殖投资策略(OREx)在整个生长过程中具有"n"型变化特征,说明长苞铁杉种群有实现生殖与恢复的可能,但能力有限.     

耦合反硝化的CANON生物滤池脱氮研究

为探究有机物对全程自养脱氮(CANON)工艺的脱氮性能的影响,采用上向流火山岩填料反应器处理模拟废水,在反应器最优工况下实现亚硝化、厌氧氨氧化与反硝化的耦合.结果表明,滤柱在氨氮浓度为200mg/L时的最优总氮去除率均值可达76.73%,总氮去除负荷为2.82kgN/(m3·d).C/N为0.2的有机物水平对反应器的脱氮效果具有促进作用,并可通过HRT的调节实现总氮去除率大于89%(理想条件下CANON的最大脱氮率).因此,通过控制C/N可以提升滤柱氮素去除效率.     

Behavior of aqueous stable colloidal nano-C60 aggregates exposed to TX100 micelles under different environmental conditions

C₆₀, as one of carbon nanomaterials widely used in various fields, could be released into the water environment thus exerting some potential health risks to human beings. This work examined the behavior of aqueous stable colloidal nano-C₆₀ (nC₆₀) aggregates under different environmental conditions including Polyethylene glycol octylphenol ether (TX100) micelles concentration, pH, and reaction time when exposed to TX100 micelles. Results show that the nC₆₀ aggregates became more dispersive and restored the capability of generating the singlet oxygen when exposed to TX100 micelles. With the increase of TX100 concentration, smaller average size of nC₆₀ aggregates was observed in dynamic light scattering (DLS) analysis, the fluorescence intensity of TX100 was more quenched by nC₆₀ aggregates, and the kinetic rate constant of generating the singlet oxygen for nC₆₀ aggregates was improved. The mean size of nC₆₀ aggregates in the presence of TX100 had no obvious variations when the pH ranged from 4 to 8. The longer reaction time between nC₆₀ aggregates and TX100 led to a higher kinetic rate constant of generating the singlet oxygen. Collective data suggest that variations in physicochemical properties of nC₆₀ aggregates are strongly dependent on the surrounding media under different environmental conditions and directly govern nC₆₀’s transport behavior and potential toxicity.     

进水C/N对富集聚磷菌的SNDPR系统脱氮除磷的影响

为了解富集聚磷菌(PAOs)的同步硝化反硝化除磷(SNDPR)系统的脱氮除磷特性,采用延时厌氧(180min)/低氧(溶解氧0.5~1.0mg/L)运行的SBR反应器,以实际生活污水为处理对象, 通过投加固态乙酸钠调节进水C/N值(约为11,8,4,3),考察其对系统脱氮除磷特性及同步硝化反硝化(SND)脱氮率的影响.结果表明:C/N对系统的除磷性能没有影响,出水PO43--P浓度均稳定在0.3mg/L左右,这是由于系统内聚磷菌(PAOs)含量高,且在低氧段可同时发生好氧吸磷与反硝化吸磷.随着C/N的增大,出水NH4+-N浓度升高,C/N下降时,出水NO3--N浓度升高.此外,随着C/N的减小,厌氧段反硝化所消耗的COD占进水COD的比例增大,SND可利用的内碳源-PHAs储存量减少,但PHV的利用率增加;当C/N为4~8时,SND现象最明显,SND脱氮率达50.8%,而其它C/N条件下,SND脱氮率都有相应程度的减弱.C/N为8时,系统出水综合指标最好,TN去除率高达80.8%.     

转cry1Ab和epsps基因玉米C0030.3.5对大型蚤(Daphnia magna)的生态毒性研究

随着抗虫和耐草甘膦除草剂转基因玉米的迅速推广和种植,其环境安全性也越来越成为人们关注的焦点。为探讨抗虫耐除草剂转基因玉米C0030.3.5(外源基因cry1Ab和epsps)对水生动物环境的安全性,以模式生物大型蚤(Daphnia magna)为指示生物,分别使用1.5 g·L~(-1)C0030.3.5玉米粉和其非转基因对照DBN318玉米粉饲喂大型蚤28 d,探讨C0030.3.5玉米对大型蚤生长和繁殖的影响。结果显示,C0030.3.5玉米粉组大型蚤与亲本DBN318组大型蚤相比,体长、存活率、新生幼蚤总数等没有显著性差异(P0.05)。28 d饲喂实验结果表明,抗虫耐除草剂玉米C0030.3.5没有对大型蚤生长和繁殖产生不良影响。上述研究结果为转基因玉米的商业化种植和安全管理提供科学数据。     

Stable C and N isotope analysis elucidated the importance of zooplankton in a tropical seagrass bed of Santiago Island,Northwestern Philippines

The role of zooplankton in a tropical seagrass ecosystem was investigated in milkfish farms pollution-impacted and -unimpacted seagrass beds in Santiago Island coral reefs, Northwestern Philippines. The aim was to compare between the two sites: (1) abiotic factors and zooplankton community parameters, and (2) the trophic structure using C and N stable isotopes. Low water (98–119?mV) and sediment (–121 to ?138?mV) Oxidation Reduction Potential values indicated a reducing environment in the impacted site. Zooplankton in the impacted site showed the typical community response to eutrophication (low diversity, but high total abundance due to the dominance of the cyclopoid copepod Oithona oculata), generally few elevated δ¹⁵N values, but a significant shift towards depleted ¹³C due to the organic enrichment of fish-farm feeds. Apart from suggesting a highly complex food web with POM and zooplankton as main food sources in the unimpacted site, the Bayesian mixing model simulation generated reduced complexity in feeding interactions between basal sources, zooplankton, and fish including adults of a key fish species, Siganus fuscescens, in the impacted sites. In this study, C and N stable isotope analysis has clarified the importance of zooplankton as fish prey in a seagrass bed food web.     

Assessment of the Ecological Integrity of Traunsee (Austria) Via Analysis of Sediments and Benthic Microbial Communities

Since nearly one hundred years Traunsee experiences the import of tons of liquid and solid waste originating from salt and soda production. Today, the lake exhibits chloride concentrations of up to 170 mg L^-1 and 19% of the lake floor are directly or indirectly influenced by industrial deposits (ID). Based on the comparison of several microbial parameters in unaffected, directly affected and intermediate lake bottom sediments, the ecological integrity of the lake was evaluated. The highly alkaline ID, which were exclusively colonized by microorganisms, harbored a bacterial community reduced by a factor of 10 in abundance and biomass compared to undisturbed sediment areas within the lake. The bacterial community of ID was furthermore characterized by a reduced content of actively respiring cells (INT-formazan reduction), a lower frequency of dividing cells (FDC) and a significantly reduced cell and biomass production. A 80 to 90% reduction in carbon recycling is estimated for the area exclusively covered by ID. Protists, although occasionally absent from the industrial sediments, were in general found to be less sensitive to the contaminant stress. Differences in alkalinity and dissolved organic carbon (DOC) concentrations of sediment porewaters as well as the total organic content and C/N ratios of sediments partly explain the microbial pattern observed at the various sampling sites. Possible consequences of the continuous industrial tailings for the whole lake ecosystem and the validation of the ecological integrity are discussed.     

基于B/S与C/S模式的铁路运输安全管理信息系统

随着我国铁路运输业的迅速发展 ,对铁路运输安全管理不断提出新的要求。解决安全管理问题一是要不断提高员工的安全素质 ,提高安全防范意识及事故处理能力 ;更重要的是运用安全管理信息技术 ,通过建立安全管理信息系统来提高安全管理水平 ,降低事故的发生。笔者综合考虑C/S模式在信息管理、办公自动化等事务处理和B/S模式在信息浏览、查询和发布方面的优势 ,采用B/S和C/S模式相结合的混合模式开发了铁路运输安全管理信息系统。结合为某铁路运输企业开发的系统 ,论述了该系统的设计和实现     

基于C/S+B/S混合模式的企业安全生产信息管理系统研究

安全生产是企业永恒的主题,良好的安全生产环境和秩序是企业可持续发展的重要保障.本文在综合分析了B/S、C/S结构的基础上,提出了基于计算机技术、网络技术、数据库技术的企业安全生产信息管理系统的构想,并对建立该系统的关键技术及系统集成进行了分析和研究.开发出了基于B/S C/S混合模式的企业安全生产信息管理系统,它能为预防事故发生提供重要的参考,为企业安全管理和事故应急决策提供重要的手段.     

长江三角洲顶部冰后期地层的沉积特征

钻探证实,镇江市谏壁镇长江北岸高桥镇北部埋藏硬粘土层,之上为冰后期松散沉积物.沉积物主要为粉砂、粘土质粉砂、砂泥互层,中部局部夹含细砾中细砂,顶部见淤泥质粘土;夹数十层植物炭屑层;以水平纹理为主,局部见小型交错层理、波状层理.表明冰后期以来该地处于水动力较弱的河湖环境,为多期湖沼相沉积夹汊道河流相沉积,局部有海相沉积物加入.根据碳化植物碎屑14C年龄,推测冰后期底界年龄约13 000 aBP,海侵到达该地的时间约为9 000 aBP,海侵最高位时间约为6 500 aBP.冰后期平均沉积速率约为4.9 m/ka,湖沼相3.4～6 m/ka,河流相10～15 m/ka.对全新统的底界年龄和海相层的埋藏深度进行了讨论.