Vegetation patterns and nature reserve construction in an extremely-arid desert in Anxi,NW China's Gansu Province

Anxi County is located in the northwestern part of the Hexi Corridor in gansu Province and has the sole national level nature reserve of extremely-arid desert in China.Phytosociological methods (Braun-Blanquet,1964) are used to classify plant community types in this area.Eleven are disting uished,including six of deserts,four of oases and one transitional type between deserts and oases.Direct gradient analysis (DCA) is employed to correlate the distribution of plant communities to physiogeographic conditions.This study makes clear that water is the most important ecological factor for the distribution of plant species and communities in this area.The effects of water have been demonstrated in different ways.A vegetation gradient from lower altitude to higher altitude in the southern part of the reserve is driven by a precipitation gradient.The effects of the depth of ground water table contribute to the differentiation of vegetation from desert to oasis in the flat area.In a finer scale,the washed gullies have obviously higher species richness and also higher vegetation cover than the surround gobi surfaces,possibly caused by the effects of floods.The vegetation patterns demonstrate that the area of Anxi County is a complete landscape unit.The range of the current nature reserve is not large enough for the purpose of conserving the unique biodiversity in this area.     

Simultaneous adsorption and immobilization of As and Cd by birnessite-loaded biochar in water and soil

Environmental Science and Pollution Research - A novel biochar was prepared by loading birnessite to improve its capability to simultaneously adsorb As(III), As(V), and Cd(II) in water and soil....     

低浓度废水厌氧处理中不同动力学模型对比研究

采用厌氧颗粒污泥处理低浓度废水来启动实验规模的沼气提升厌氧反应器,以啤酒废水为例,厌氧反应器在温度(35±1)℃和进水COD浓度在2100~2400mg/L条件下,通过提高进水量方式,来缩短水力停留时间HRT和提高有机负荷OLR.用First-order、Monod and Contois、Grau second-order和Modified Stover–Kincannon动力学模型,考察在不同的HRT和进水浓度Si条件下,出水浓度Se与前两者的关系,确定动力学参数.实验结果表明:First-order和Monod and Contois模型不适用本实验,Grau second-order和Modified Stover–Kincannon模型适用,通过后两个模型公式分别比较实验值Se与计算值Se的差别,Grau second-order模型比Modified Stover–Kincannon模型更接近实验值.     

氟吡菌胺对斑马鱼的毒性效应

采用斑马鱼胚胎发育技术和传统毒理学方法, 研究了氟吡菌胺对斑马鱼胚胎、成鱼及仔鱼的毒性效应.结果发现,氟吡菌胺对3个阶段斑马鱼均具有致死能力,对仔鱼LC50(48h)值为0.204mg/L,成鱼LC50(96h)为0.286mg/L,幼鱼LC50(96h)为1.489mg/L.研究表明,0.0596mg/L以上浓度的氟吡菌胺对斑马鱼胚胎均有一定程度的致死效应,高浓度处理组胚胎出现心包囊肿、卵黄囊不吸收、黑色素沉积少及鱼体弯曲等症状;氟吡菌胺对斑马鱼成鱼进行14d暴露后,处理组成鱼体重下降,产卵量减少,有效卵量降低; 0.0298mg/L处理组144h子代仔鱼存活率虽然比较高,但存活鱼大部分出现心包囊肿、体弯曲等畸形.上述结果说明,水体中残留的氟吡菌胺对于斑马鱼各生命阶段的生长发育均具有潜在的危害.     

Evaluation of bioaugmentation and biostimulation on arsenic remediation in soil through biovolatilization

Arsenic (As) removal through microbially driven biovolatilization can be explored as a potential method for As bioremediation. However, its effectiveness needs to be improved. Biostimulation with organic matter amendment and bioaugmentation with the inoculation of genetic engineered bacteria could be potential strategies for As removal and site remediation. Here, the experiments were conducted to evaluate the impacts of rice straw and biochar amendment, inoculation of genetic engineered Pseudomonas putida KT2440 (GE P. putida) with high As volatilization activity, on microbial mediated As volatilization and removal from three different arseniferous soils. In general, the addition of rice straw (5%) significantly enhanced As methylation and volatilization in comparison with corresponding non-amended soils. Biochar amendments and inoculation of the GE P. putida increased As methylation and volatilization, respectively, but less than that of rice straw addition. The effectiveness of As volatilizations are quite different in the various paddy soils. The combined amendments of rice straw and GE P. putida exhibited the highest As removal efficiency (483.2 μg/kg/year) in Dayu soil, with 1.2% volatilization of the total As annually. The highest water-soluble As concentration (0.73 mg/kg) in this soil could be responsible for highest As volatilization besides the rice straw and bacteria in this soil.     

Effects of multi-phase inoculation on the fungal community related with the improvement of medicinal herbal residues composting

Environmental Science and Pollution Research - Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent...     

纳氏试剂比色法测定水体中氨氮常见问题与解决办法

阐述了纳氏试剂比色法测定氨氮实验中涉及的各反应过程原理,对实验中常见的6个问题分别作了探讨,提出了解决办法。     

Cd2+胁迫下中肋骨条藻细胞内多胺的生理响应

通过室内添加Cd2+培养中肋骨条藻(Skeletonema costatum),开展了Cd2+胁迫对中肋骨条藻生长的影响及藻细胞内超氧化物歧化酶(SOD)、二胺氧化酶(DAO)、多胺氧化酶(PAO)的活性以及丙二醛(MDA)和各形态多胺含量变化的实验,以探究多胺对于海洋微藻在重金属胁迫下的响应及生理作用.结果显示,Cd2+对中肋骨条藻的生长产生胁迫作用,且Cd2+浓度越大对藻细胞生长的抑制作用越强.Cd2+胁迫下中肋骨条藻细胞内MDA含量略有升高,SOD活性显著降低,DAO和PAO活性分别增强.随着Cd2+胁迫作用的增强,藻细胞内游离态腐胺(Put)、亚精胺(Spd)、精胺(Spm)含量先降低后升高;结合态Put、Spd和Spm含量先升高后降低;束缚态Put、Spm和Spd含量及Put总量和Spm总量升高.表明Cd2+胁迫会导致中肋骨条藻细胞产生氧化损害,同时细胞内DAO和PAO活性的增强以及游离态Put、束缚态Spd和Spm、Put总量和Spm总量的升高可能会增强藻细胞抵抗Cd2+胁迫的能力.     

Characterization of phenol degradation by high-efficiency binary mixed culture

Background, aim, and scope  

Two new high phenol-degrading strains, Micrococcus sp. and Alcaligenes faecalis JH 1013, were isolated. The two isolates could grow aerobically in mineral salts medium containing phenol as a sole carbon source at concentration of 3,000 mg L⁻¹. It was found that the binary mixed culture of the two isolates possessed good potential for phenol removal.     

乳酸菌复合系SFC-2处理水稻秸秆的效果

以处理农作物稻秆,减轻环境压力为目的,将本实验室筛选的乳酸菌复合系SFC-2接种到水稻秸秆,研究了其饲料化效果.结果表明,接种处理与未接种处理相比外观上颜色发黄发亮,松软酸香,发酵30 d后,接种处理的pH降至3.8,对照为4.1.同时发酵料中乳酸生成量增加,尤其是L-乳酸增加了约2倍,粗蛋白含量提高了10.16%,粗纤维含量降低了3.2%.通过变性梯度凝胶电泳（DGGE）分析发酵过程中微生物菌系变化,接种SFC-2后,复合系中的主要组成菌Lactobacillus plantarum,Lactobacillus fermentum和Lactobacillus paracasei等菌株迅速成为发酵料中的优势菌群,相应未接种对照中可见的Enterobacter sakazakii, Pantoea agglomerans, Enterobacter endosymbiont, Pantoea ananatis等杂菌被抑制,发酵品质得到明显改善.