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1.
石油降解菌的分离、鉴定及其降解能力的研究   总被引:12,自引:0,他引:12  
从含油污泥中,筛选出能以20 # 机械润滑油为唯一碳源的3 株石油降解菌菌株,经鉴定分别为动胶菌属( Zoogloea sp .) 、氮单胞菌属( Azomonassp .) 和假单胞菌属( Pseudomonas sp .) .通过其降解能力的测试,以动胶菌 D2 菌株对20 # 机油的降解能力最强:在含油浓度ρ= 500 ~1 500 mg/ L 的摇瓶试验中,其除油率为20 .8 % ~25 % .利用动胶菌 D2 菌株进行生物接触氧化法处理含油废水模拟试验,当入流浓度为1 000 mg/ L 时,除油率可达90 .5 % ~100 % .这一结果表明,动胶菌 D2 菌株生物接触氧化法处理含油废水具有很好的应用前景  相似文献   

2.
耐低温混菌降解苯系物的特性及菌种鉴定研究   总被引:1,自引:0,他引:1  
周月明  刘娜  张兰英  刘鹏  高松 《生态环境》2010,19(8):1893-1900
以吉化双苯厂被硝基苯、苯系物(BTEX)污染的土壤为菌源,经过筛选驯化得到一组在低温条件(10℃)下可降解苯系物(BTEX)的混菌。室内研究表明,在10℃,pH=6.8,苯系物(BTEX)总质量浓度200mg·L^-1的条件下,84h后该菌对苯、甲苯、乙苯、二甲苯的降解率依次为93.2%、95.6%、91%、88.4%、对6种质量浓度的苯系物(BTEX)污染物中最难降解的苯进行降解动力学曲线模拟,当苯质量浓度小于17.48mg·L-1时,降解符合一级降解动力学,当苯的质量浓度为17.48~195.30mg·L^-1时,降解符合零级降解动力学、该混菌降解效果稳定、适应环境能力强,经80次传代后仍能保持良好的降解效果,且在6个不同地区含有不同背景组成的地下水中降解效果稳定、应用Biolog细菌自动鉴定系统和16SrDNA序列分析方法对降解率较高的3株菌B2、B4、B6作菌种鉴定,B2为嗜麦芽糖寡养单胞菌(Stenotrophomonas maltophilia),B4为斑生假单胞菌(Pseudomonas maculicola),B6为多刺假单胞菌(Pseudomonas spinosa)。  相似文献   

3.
段海明 《生态环境》2012,(9):1608-1613
筛选分离降解微生物解决有机磷农药残留给水体和土壤环境带来的污染问题是一项可行的生物修复技术。采用富集培养和定时取样分析有机磷农药残留的方法,分离驯化出三株能够降解有机磷农药的细菌,研究了其形态特征和生理生化特性并对其16SrDNA序列进行了分析,同时比较了三菌株对甲基对硫磷(Methyl-parathion)、毒死蜱(Chlorpyrifos)和_二唑磷(Triazophos)的降解特性。结果表明:通过富集培养得到10菌株具有降解甲基对硫磷和毒死蜱的能力,比较确定HY-1、HY-2和HY-4三菌株作为研究对象,经鉴定为蜡状芽孢杆菌(Bacilluscereus)的不同菌株,三菌株在Genbank上的登录号分别为:eu915687、eu915686和eu915688。在甲基对硫磷质量浓度为50mg·L-1时,三菌株72h的降解率分别为91.7%、87.7%与92.4%.降解率无显著性差异(P〉0.05),当甲基对硫磷质量浓度增加到100mg·L-1时,三菌株对甲基对硫磷的降解率有所下降,其中HY-2对甲基对硫磷的降解率下降最大达23%,且和其他两菌株有显著性差异(P〈0.05o三菌株72h对100mg·L-1毒死蜱的降解率分别达到64.8%、53.7%和56.5%,在不同的毒死蜱初始质量浓度下,HY-1和HY-4两菌株对毒死蜱的降解率无显著性差异(P〉0.05),HY-2与HY-1、HY-4两菌株有显著性差异(P〈0.05o三菌株对三唑磷的降解率均较低,其中HY-2对初始质量浓度为100mg·L-1三唑磷的降解率最高仅为20.7%,其余两菌株对三唑磷的降解率比HY-2低且无显著性差异(P〉0.05o可以得出本研究分离得到的蜡状芽孢杆菌不同菌株对有机磷农药的降解存在多态性。  相似文献   

4.
微生物降解苯胺的特性及其降解代谢途径   总被引:7,自引:0,他引:7  
从活性污泥中分离得到的一株细菌 A N3 ,能以苯胺为唯一碳、氮源和能源生长,苯胺的最高降解浓度5000 mg/ L 以上,鉴定为食酸丛毛单胞菌( Comamonas acidovorans) . A N3 还可降解乙酰苯胺,但不利用其他取代类苯胺,该菌株的生长细胞和完整细胞降解苯胺的最适p H7 .0 ,最适温度30 ℃,且完整细胞降解苯胺的活性比生长细胞高得多.9 种金属离子对该菌株的生长细胞和完整细胞降解苯胺均有不同程度的抑制作用,尤以 Ag + 和 Hg2 + 为明显. A N3 含有苯胺加双氧酶、邻苯二酚2 ,3加双氧酶等一系列与苯胺降解有关的酶类,它们均为诱导酶.对苯胺降解的关键酶进行了酶动力学特性的研究,根据这些结果提出了该菌株降解苯胺的代谢途径.  相似文献   

5.
考察了在不同温度、pH值、摇床转速、氮源等环境和营养条件下,间甲酚降解菌Citrobacter farmeri对降解速率和降解过程中反应液的TOC值、紫外吸收及酶活的变化.结果表明,Citrobacter,farmeri降解间甲酚的最适温度为35℃,培养基初始pH值为6.5-8.0,摇床转速为170 r·min~(-1),无机氮比有机氮和氨态氮比硝态氮更利于Citrobacter farmeri对间甲酚的降解;当间甲酚初始浓度低于375mg·l~(-1)时,Citrobacter farmeri降解间甲酚符合零级动力学方程;间甲酚初始浓度约为60 mg·l~(-1)时约4 h完全降解,TOG的去除率8 h内可达到77%,之后几乎不变;Citrobacter farmeri可完全降解约600 mg·l~(-1)的间甲酚,表现出高效与强耐受能力的结合.对酶活的测定发现,儿茶酚1,2-双加氧酶有明显增大,初步判断Citrobacter farmeri以邻位裂解的途径对间甲酚进行降解.  相似文献   

6.
以Ti(OC4H9)4为原料,溶胶-凝胶法制备纳米TiO2薄膜,用原子力显微镜(AFM)观察了纳米TiO2薄膜的形貌,X-射线衍射(XRD)考察相同条件下粉体的相结构.研究水中橡梳栲胶的光催化降解行为.结果表明,橡梳栲胶的降解可用Langmuir-Hinshelwood方程来描述,即浓度较高时,栲胶降解液的光催化降解符合零级动力学方程;浓度较低时,栲胶降解液的光催化降解符合一级动力学方程.外加H2O2对橡梳栲胶的光催化降解有极大的促进作用,但这种促进作用会因为光生电子效率的影响而有一个极限值.在远离橡梳栲胶溶液等电点的起始pH值条件下光催化降解效果较好,且在碱性条件下的降解速率高于酸性条件下的降解速率。  相似文献   

7.
常温下过硫酸盐氧化降解水中对氯苯胺   总被引:1,自引:0,他引:1  
杜肖哲  张永清 《环境化学》2012,31(6):880-884
研究了常温下初始pH值对过硫酸盐氧化降解水中对氯苯胺(PCA)动力学过程的影响,并探讨了PCA降解的机理.结果表明,室温下,PCA的降解符合准一级动力学方程;pH值为3、5、7、9和11时,其一级动力学常数k分别为0.03×10-4、0.12×10-4、0.28×10-4、0.26×10-4和0.27×10-4s-1;酸性体系不利于PCA的降解,pH 7时PCA的降解速率最大,半衰期为6.88 h.通过LC/MS和GC/MS鉴定得到PCA降解的4种主要中间产物,分别为对氯硝基苯、对苯醌、1-(4氯苯)-3苯基脲和5-氯-2-(4氯苯二氮烯)苯酚,并在此基础上探讨了过硫酸盐氧化降解PCA的可能途径.  相似文献   

8.
降解褐煤菌种选育及降解产物研究   总被引:10,自引:0,他引:10  
通过对分离自洗煤厂的一株青霉菌进行人工诱变,选育出一株具有较强降解褐煤能力的突变株.将褐煤加到平板培养的该菌株上,经过36 h 开始被降解.将该菌株用摇瓶培养3 d ,其培养液也能降解褐煤.元素分析结果表明,降解物中 H、 O、 N 的元素质量分数( w/ % ) 比原煤均有所升高,而w( C)/ % 明显下降.降解产物的经验分子式可写为 C100 H144 O58 .2 N10 .0 S1 .18 ,经凝胶过滤法测,定其 Mr 分布在(2 ~8) ×104 之间; 其红外吸收光谱与原煤相比也有一定的变化. 这些结果说明生物降解过程中褐煤的组成和结构发生了一定的变化  相似文献   

9.
水势与用氮量对土壤中石油降解的影响   总被引:11,自引:0,他引:11  
研究了石油降解过程中,土壤有效氮的动态变化,不同用氮水平在两种土壤上对石油降解速率的影响,以及石油降解的土壤水势条件。结果表明,石油对土壤的污染没有影响土壤水势;在土壤水势为-100 ̄-20kPa范围内,水势的降低没有影响石油分解,而当土壤水势为-1000kPa时,石油降解速率与对照相比下降了10% ̄35%,在壤土上,肥料氮添加在碳(石油中碳)氮(肥料中氮)比为90时,石油降解最快,过多施用肥料氮  相似文献   

10.
研究了石油降解过程中,土壤有效氮的动态变化,不同用氮水平在两种土壤上对石油降解速率的影响,以及石油降解的土壤水势条件。结果表明,石油对土壤的污染没有影响土壤水势;在土壤水势为-100~-20kPa范围内,水势的降低没有影响石油分解,而当土壤水势为-1000kPa时,石油降解速率与对照相比下降了10%~35%。在壤土上,肥料氮添加在碳(石油中碳)氮(肥料中氮)比为90时,石油降解最快;过多施用肥料氮会降低石油的分解速率。  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

13.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

14.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

15.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

16.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

17.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

18.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

19.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

20.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

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