城市生态系统的预测与综合评价的思想体系

本方针对国内外城市生态系统的研究,提出了一套预测一评价一对策的思想体系,并对其预测、评价方法作了初步理论探讨.     

Degradation of crude oil by a mixed population of bacteria isolated from sea-surface foams

A mixed bacteria population (EM₄) was isolated from foams formed on the surface of a zone chromically polluted by hydrocarbons (Gulf of Fos, French Mediterranean coast, October 1981). The population was able to degrade crude oil very effectively in the presence of sea water supplemented with nitrogen, phosphorus and iron. The percentage of hydrocarbon degradation was 81% at 30°C, pH 8, and partial oxygen pressure of 100%. After 12 d incubation, 92 and 83% of satured and aromatic compounds (mono-, di- and triaromatics) were degraded, respectively, as well as 63% of polar products and 48.5% of asphaltenes. Maximum degradation was attained at a sodium chloride concentration of between 400 and 800 mM with Population EM₄, which is constituted of 8 strains, four of which are weak halophiles. Bacterial growth on hydrocarbons induces the production in the culture medium of surface-active agents which are able to emulsify the substrate. There is high specificity between the nature of the growth substrate and such emulsifying activity, particularly as far as petroleum is concerned: only the culture medium from Population EM₄ is able to emulsify petroleum. These surface-active agents contain sugars and lipids (fatty acids, mono- and diglycerides). The foams, which always contain a high concentration of both hydrocarbons (100 to 180 mgl^-1) and bacteria that are able to grow on these types of substrates, have a strong emulsifying activity. Our results would seem to demonstrate the importance of biosurfactants in the elimination of hydrocarbons from polluted biotopes.     

A simple and precise method for fitting a von Bertalanffy growth curve

The parameter K of the von Bertalanffy equation, as developed by Beverton and Holt (1957), is first estimated by the relation $$\log _e \left( {dL_t /dt} \right) = A - Kt$$ where dLt/dt denotes growth increments per a unit of age, t denotes age, and A is a constant. The K estimate is used to evaluate L∞; $$L_\infty = \left( {e^K \sum\limits_2^n {L_t - \sum\limits_1^{n - 1} {L_t } } } \right)/\left( {n - 1} \right)\left( {e^K - 1} \right)$$ The L∞ estimate is used to estimate t _o, and to obtain a better estimate for K; $$\log _e \left( {1 - L_t /L_\infty } \right) = - Kt + Kt_0 $$ The K estimate may be used to obtain another estimate for L∞. Solved examples show that a single iteration is sufficient to obtain fitted equations which are, on the average, as precise as equations fitted by the least squares method shown by Tomlinson and Abramson (1961). This new method can be used, with a slight modification, for the second equation given above, if growth data have unequal age intervals. The variance of K, t _o and log _e L∞ can be estimated by applying the simple methods used in the case of straight-line relationships.     

Nutrients and biomass distribution in the Gulf of Aqaba (Elat), Red Sea

The distribution of phosphate, nitrate and silicate values obtained from 300 samples and of biomass determined by displacement volume in about 1,900 vertical plankton hauls (65, 200 and 330 m) collected from 8 oceanographic station during 1974–1975 in the Gulf of Aqaba (Elat) are summarized and illustrated by crosssections. Generally, the Gulf is poor in nutrients and the data indicate that it is filled with upper (150 m) Red Sea waters, flowing in over the sill of Tiran. Nutrient content of the upper and deep waters immediately outside the sill are well within the known range of those in the northern Red Sea. Biomass values are relatively low in the Gulf are generally similar to those reported from the northern Red Sea. Both nutrients and biomass values display seasonal and bathymetric variations in the Gulf and outside the sill.     

The impact of motorcycle traffic on soil and vegetation of stabilized coastal dunes, Israel

This study aimed to assess the response of soil and annual plant vegetation of stabilized coastal dunes in Israel, to varying intensities of off-road motorcycle (ORM) traffic, and to assess their resistance and resilience to such a disturbance. A standard experimental procedure that included 0, 20, 50, 100 and 200 ORM straight passes and 150 ORM turn passes was used. Plant ground cover, mean plant height, species richness, species diversity, soil penetrable depth, organic matter and moisture contents were measured on several dates within a period of 372 days after the experiment. Results have shown that: (1) ORM passes had a significant immediate impact on annual plants that increased with traffic intensity. The impact on the soil was detected only as an increase of penetrable depth. (2) The maximum impact on annual plants was observed in the wheel ruts and turn areas. The impact on the area between the wheel ruts and on the margins outside the wheel ruts was indirect and smaller. (3) Annual plant ground cover and mean plant height were less sensitive parameters than species richness and species diversity for determining the impact of ORM traffic on the area. (4) One year after the experiment, soil and annual plant vegetation in all passes were very similar to their pre-experimental condition. This indicates high resilience and recovery potential of the Mediterranean stabilized coastal dune ecosystem to ORM disturbance.     

Comprehensive utilization of residues of Magnolia officinalis based on fiber characteristics

Journal of Material Cycles and Waste Management - The traditional Chinese medicinal plant Magnolia officinalis has a wide range of applications; including more than 200 kinds of patented Chinese...     

采用络合萃取法从维生素B12发酵废液中回收丙酸

采用络合萃取法回收维生素B12发酵废液中的丙酸,确定了络合萃取的最佳工艺条件：以0．5mol／L的磷酸三丁酯(TBP)为络合剂,油水比(体积比)为1：2,常温下萃取30min。在最佳工艺条件下单级萃取率为56％左右,四级萃取率可达98％以上。络合萃取过程中使用的有机溶剂可反复使用,使成本大大降低。     

2012年上半年我国南方地区极端阴雨天气评价——以湖南省为例

基于湖南省97个地面气象观测站观测资料,根据所选定的阴雨天气评价指标,运用数理统计方法,对2012年上半年湖南省阴雨天气特征及强度进行分析评估,结果表明,阴雨天气阶段性特征显著,属隆冬至初春历史罕见的寡照低温多雨事件与初春至初夏的极端多雨寡照事件的组合。同时根据社会调查数据对阴雨天气的影响展开多方位分析,得出低温阴雨天气不仅对农业造成了重大影响,而且对水利、交通、建筑业等多行业和人们身体健康也有较大影响,以此提出了应对极端天气气候事件的对策建议。     

Screening and detection of biomarkers in chickpea plants exposed to chromium and cadmium

A broad screening protocol, covering the most general phytochemical groups of compounds, was developed on the basis of high performance thin layer chromatography (HPTLC). A total of six TLC systems, comprising three derivatization reagents, two stationary phases and two mobile phases, were included. The screening method was applied for the identification of biomarkers in the chickpea plant exposed to cadmium and chromium. The biomarkers were selected on the basis of significant changes (0.26-4.6 fold) in concentration levels of phytochemicals. Totally, five different amino acids, three organic acids, one sulphur containing compound and one sugar were identified as biomarkers in chickpea exposed heavy metal.     

利用改进的SOS/umu方法检测水处理过程中污染物的遗传毒性效应

SOS/umu遗传毒性测试方法被广泛应用于化合物和复杂混合物遗传毒性的评价,但是目前已报道方法的实验周期长达17 h,给实验操作带来了不便,因此亟需对常规方法进行改进。建立了测试周期可小于8 h(2 h预培养,4.5 h暴露培养) 的SOS/umu快速测定方法之后,应用改进后的方法对5种典型遗传毒性物质, 4-硝基喹啉1-氧化物(4-NQO)、丝裂霉素C(MMC)、甲磺酸甲酯(MMS)、2-氨基蒽(2-AA)和苯并芘(BaP)进行测定,结果表明,改进后的SOS/umu方法对4-NQO、MMC、MMS、2-AA和BaP的检测限分别为0.013±0.0031、0.031±0.0028、229.18±60.51、2.29±1.22和1.28±0.0698 μmol·L^-1,优于或者相当于报道方法。采用经典方法和改进后的方法对全国两个地区6个环境水样的遗传毒性进行测定,结果表明,两种方法检测出的6个环境水样的遗传毒性强度无显著性差异。另外,将研究方法应用于北方某市甲乙两个水厂原水、出厂水和管网水的遗传毒性评价,结果表明,两个水厂的原水、出厂水和管网水均表现出一定的直接遗传毒性,对应的4-NQO当量浓度(TEQ4-NQO)在0.0012 μg·L^-1至0.0129 μg·L^-1之间;加入鼠肝微粒体酶系统(S9)后,仅有乙水厂的管网水检测出极其微弱的遗传毒性效应。以上研究结果表明,改进后的SOS/umu快速测定方法能够实现在短时间（8h）内完成环境化合物及环境样品的遗传毒性检测,为筛选和评价化合物和复杂环境样品的遗传毒性提供了更为快捷的手段。