萘好氧降解污泥强化培养特性与降解效能研究

以制药废水中特征污染物萘为研究对象,在葡萄糖共基质与萘为唯一碳源存在的情况下,采用按特征污染物浓度梯度增加的方式对好氧活性污泥驯化,对培养过程中污泥对萘降解特性和微生物特性进行研究。实验结果表明,萘对微生物有抑制作用,但萘好氧降解污泥经过7个周期(2个月)强化培养,可适应仅以萘为碳源的环境下生存,污泥中细菌种类主要为Acidovorax(食酸菌属),可处理有机物萘浓度达60 mg/L,对萘降解率从89%升稳定达到93.3%以上,SOUR值稳定在9.58 mgO_2/(gMLSS·h)以上,具备了在含萘制药废水深度处理工程应用的条件。     

硫酸盐还原型甲烷厌氧氧化菌群驯化及其群落特征

甲烷的温室效应是二氧化碳的26倍,高浓度硫酸盐废水对水体、土壤和植物均有危害.硫酸盐为氧化剂的甲烷厌氧氧化是减少甲烷的主要途径之一.本研究以硫酸盐作为电子受体,驯化培养硫酸盐还原型甲烷厌氧氧化菌群,采用PCR-DGGE技术分析细菌和古菌菌群多样性和群落结构特征,并对其中的优势菌进行系统发育分析.DGGE指纹图谱结果表明,硫酸盐的加入使微生物群落结构和优势种群数量发生了明显的改变,其增强了甲烷氧化古菌和硫酸盐还原细菌的丰度,加入硫酸盐驯化的菌群,其细菌群落多样性增加而古菌群落多样性略微减少.典型条带测序结果显示,驯化后菌群的优势菌种主要包括螺旋体门(Spirochaetes),除硫单胞菌目(Desulfuromonadales)、甲烷八叠球菌目(Methanosarcinales)和甲烷丝状菌属(Methanosaeta)等.驯化菌群的甲烷厌氧氧化研究结果显示,甲烷厌氧氧化的同时伴随硫酸盐的还原,甲烷的氧化产物为二氧化碳,硫酸盐的转化产物为硫化氢和硫单质.     

甲烷厌氧氧化协同硝酸盐还原菌群驯化及其群落特征

伴随硝酸盐还原的甲烷厌氧氧化是协同减少环境中硝酸盐及甲烷的有效途径.利用实验室废水处理厌氧污泥、污水处理厂厌氧污泥和填埋场覆土驯化富集硝酸盐还原型甲烷厌氧氧化菌群.考察菌群的甲烷氧化效果,结果发现接种污水处理厂厌氧污泥体系甲烷转化量最大,为0.05 mg·d-1.微生物群落结构分析显示,该体系中甲烷微菌和甲烷八叠球菌是甲烷氧化菌,假单胞菌、梭状芽胞杆菌和热单胞菌参与了硝酸盐的还原反应.硝酸盐的量影响甲烷的转化率及菌群结构.当硝酸盐浓度为200 mg·L-1时,体系中的硝酸盐还原菌为假单胞菌和梭状芽胞杆菌;浓度增加至500 mg·L-1时,硝酸盐还原菌则是假单胞菌和热单胞菌.同时,甲烷转化率增加34.7%.研究结果为该菌群应用于含甲烷废气与含硝酸盐废水的协同处理提供科学依据.     

在 UASB 反应器中颗粒污泥的培养与应用研究

七十年代以来,世界各国出现了一批高速废水厌氧处理工艺,其中上流式厌氧污泥床(简称UASB)反应器是应用最广泛的装置之一。由于在UASB反应器中污泥的沉降性能不仅影响反应器结构,而且直接决定了反应器能否高负荷、高效率地运行,因此近几年来国内外一些学者都开始对具有优良沉降性能和高活性的颗粒污泥进行研究,但在我国,目前几乎所有的生产性UASB装置内污泥都是絮状的,处理负荷和效率都较低,本文研究了在UASB反应器中污泥颗粒化的条件和培养技术,并在此基础上对有关颗粒污泥实用性等方面的问题也进行了一定的探讨。     

Early loss and multiple return of the lower temporal arcade in diapsid reptiles

The temporal arches of diapsid reptiles have received attention for several decades. In particular, it has been observed that the lower temporal bar at the ventral margin of the cheek is frequently reduced due to the absence of a contact between jugal and quadratojugal. The loss of the arcade was formerly considered to be of high systematic value, but is now often interpreted as being autapomorphic for the respective taxon, and the presence of both arcades is generally regarded as a plesiomorphic feature. Here I show, based on a cladistic analysis as well as on further anatomical evidence, that the lower temporal arcade was lost only once in diapsid evolution, and that the presence of the arch in "higher" diapsids is secondary, which is indicated by the different ratio between jugal and quadratojugal as well as by ontogeny. This result also sheds new light on the understanding of the cheek configuration of enigmatic taxa such as ichthyosaurs and turtles.Electronic Supplementary Material  Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Urban sustainability experiments in Asia: patterns and pathways

Despite well-documented examples of urban sustainability practices in Asia, the internal mechanisms of the practices, their transferability, and their impact on urban sustainability transitions are yet to be thoroughly investigated. This paper examines 30 innovative urban practices in Asia from a system innovation and urban environmental evolution perspective, in an attempt to identify common patterns and pathways that can aid up-scaling and thereby broader application of effective sustainability practices. We developed a five-tier framework (e.g. triggers-actors-linkages-barriers-pathways) to explore whether successful broad-scale application was related to patterns within each of the tiers, or whether certain combinations of tiers lead to certain application pathways. Our results indicate the importance of policy changes and cumulative effects; the importance of local government, community and international agencies as main actors; and the prominent role of political and institutional barriers, while technology doesn’t seem to be a major barrier in urban sustainability experiment in Asia. Our results indicate that: those cases that are up-scaled through broader application often have strong vertical linkages with state or national governments; many international development agency initiatives tend to remain as experiments or duplicated elsewhere but are seldom up-scaled to change the system of practice. Nearly half of the innovative practices examined were either mainstreamed or duplicated elsewhere, suggesting that these innovative practices might play important role in sustainability transitions in Asia.     

Soil carbon sequestration in tropical agroforestry systems: a feasibility appraisal

Agroforestry is recognized as a strategy for soil carbon sequestration (SCS) under the afforestation/reforestation activities, but our understanding of soil carbon (C) dynamics under agroforestry systems (AFS) is not adequate. Although some SCS estimates are available, many of them lack scientific rigor. Several interrelated and site-specific factors ranging from agroecological conditions to system management practices influence the rate and extent of SCS under AFS, so that generalizations tend to become unrealistic. Furthermore, widely and easily adoptable methodologies are not available for estimating the SCS potential under different conditions. In spite of these, there is an increasing demand for developing “best-bet estimates” based on the current level of knowledge and experience. This document presents an attempt in that direction. The appraisal validates the conjecture that AFS can contribute to SCS, and presents indicative ranges of SCS under different AFS in the major agroecological regions of the tropics. The suggested values range from 5 to 10 kg C ha^?1 in about 25 years in extensive tree-intercropping systems of arid and semiarid lands to 100–250 kg C ha^?1 in about 10 years in species-intensive multistrata shaded perennial systems and homegardens of humid tropics.     

Effect of tunnel inclination on digging energetics in the tuco-tuco, Ctenomys talarum (Rodentia: Ctenomyidae)

Burrows play an important role for many species, providing them with shelter and access to food resources. For subterranean rodents, living underground imposes constraints on morphology and physiology. The convergence in burrow architecture among subterranean rodents has been related to the energy demands imposed by the cost of constructing an entire system. The low frequency of tunnels with downward angles steeper than 40° appears to be a common feature in burrow design. In the subterranean habitat, movements through the soil are expensive and gravity can exert important restrictions on digging energetics when individuals push out the soil removed in steeper digging angles. The aim of this study was to determine the effect of digging angle on digging energetics in Ctenomys talarum. The mass of the removed soil and burrowing speed were similar while digging metabolic rate and net cost of transport were higher in individuals digging in tunnels with angles >40° than in those digging tunnels with angles <40°. The cost of constructing a burrow in the horizontal plane differed by 20% from others in which the natural representation of tunnels >40° was considered. Even given that tunnels >40° represented only 6% of the total burrow length, burrow architecture appears to be constrained by the high energetic cost of constructing in steeper angles.     

热带海洋景观的生态系统服务替代和恢复

分析了人类利用技术手段来替代和恢复生态系统服务功能的一些尝试(如红树林海水养殖、人造海堤、人造礁等),讨论人工技术能在多大程度在替代海岸带景观的生态系统功能,生态系统的恢复项日是否既能恢复生态系统为人类提供的直接利用价值,也能恢复系统面对未来干扰的自我恢复能力.研究表明,替代项目仅能替代生态系统的某些功能,且需要耗费巨大的工程和维修费用.另外,恢复项目往往没有考虑大尺度的过程,如红树林、海草床、珊瑚礁之间物理的、生物的、生化的交互作用,造成恢复生态系统的生物多样性及抗干扰能力降低.     

Crop diversity in tropical Swidden cultivation: Comparative data from Colombia and Papua New Guinea

Traditional swidden or shifting cultivation in the tropics is commonly associated with mixed cropping, from which it is assumed to derive ecological advantages. However, considerable variation exists in the level of diversity of individual swidden communities. This is illustrated by the application of Simpson and Shannon indices to crop compositional data for such communities in the Colombian Amazon and in southwest Papua New Guinea. In these areas, both high-diversity and low-diversity swiddens are encountered, which are apparently of sustainable character. It is inferred that diverse crop communities do not have a monopoly on adaptation in swidden cultivation.     

Certification of tropical timber and deforestation: Micro monitoring without macro conditions?

Due to external effects associated with rainforest conservation, it is likely that the preferred size of rainforests is larger from the point of view of the international community than from the point of view of those who directly exploit the forests. As trade in tropical timber is the main direct link between forest exploitation and the international community, trade policy instruments have been proposed to promote sustainable forest exploitation. One such instrument is certification of internationally traded tropical timber: sustainably produced timber is labelled so that it becomes distinguishable from unsustainably produced timber. One of the aspects of the current debate is the level at which monitoring of compliance to the certification criteria should take place,i.e., at the macro (country) level or at the micro (concession) level. There seems to be a consensus that in order to be acceptable for industrialised countries' consumers, monitoring and certification should in any case take place at a micro level. However, we argue that in terms of maintaining tropical forests a firm level certification regime may be counter-effective in the short and medium run if no macro conditions are included in the certification process as well.     

Biological and economic optima in a tropical grazing ecosystem in Australia

Our aim in this study was to identify the economically optimal level of use of resources for a grazing system in tropical Australia and to compare it with the biological optimum. Grazing management trials were conducted in the Ord River irrigation area of north-western Australia. Biologists at the Commonwealth Scientific and Industrial Research Organization provided the biological data. The liveweight gains of Kimberley shorthorn steers were recorded, after a 1-year fattening period, for different grazing management strategies. Five different stocking rates were used on irrigated pangola grass (Digitaria decumbens) fertilized with nitrogen at five different rates. All other were applied at fixed, non-limiting levels.The results of the trials were modelled by a liveweight gain production function. This production function was used in an income simulation model to identify economically optimal (profit maximizing) stocking rates. This was done in two stages. First, a base analysis was undertaken on the basis o the economic conditions prevailing in September 1987. Second, sensitivity analysis was applied to the results of the base analysis. The parameters varied were the rate of interest, store cattle prices, finished cattle prices, transport costs and the length of the planning horizon.The biological optimum, when defined as maximum liveweight gain ha⁻¹, corresponds to a much higher intensity of use of resources than the economic optimum, and yields substantially lower profits or higher losses. These discrepancies increase when economic conditions worsen, or when the planning horizon of graziers is decreased from 50 to 10 years. Therefore, the adoption of the biological optimum cannot result in an econonomically stable grazing system in the medium to long term, when it is highly likely that economic parameters will fluctuate. The economic stability of the system is increased, but is still quite weak, if the economically optimal input combination is utilized. It was not possible to determine whether this economic optimum would result in long-term ecological stability because the relevant data were not collected during the trials.The relevance of management recommendations made to graziers and land administrators would be increased if these recommendations were based on an analysis of both the economic and the ecological stability of grazing systems over the medium to long term. We show in the last part of this study how this could be accomplished.     

我国热带海岛开发利用存在的生态环境问题及其对策研究

文章论述了我国热带海岛开发利用的历程。从环境污染、生态破坏和全球气候变化的影响等3个方面分析了面临的生态环境问题,主要体现在:海域污染和陆域污染;防风林、红树林、珊瑚礁生态系统的破坏,生物资源的过度开发;在全球变化和相对海平面上升影响下,自然灾害(风暴潮、海岸侵袭、海水入侵等)频繁对海岛生态环境带来新的危害,进一步加剧热带海岛的生态环境问题。最后提出热带海岛生态环境保护对策与建议:建立有效的海岛综合管理体系和机构;控制海上流动污染源和岛源污染;加强宣传,提高公众的海岛生态保护意识;加强海岛海岸带资源环境工程建设。     

From site-level to regional adaptation planning for tropical commodities: cocoa in West Africa

The production of tropical agricultural commodities, such as cocoa (Theobroma cacao) and coffee (Coffea spp.), the countries and communities engaged in it, and the industries dependent on these commodities, are vulnerable to climate change. This is especially so where a large percentage of the global supply is grown in a single geographical region. Fortunately, there is often considerable spatial heterogeneity in the vulnerability to climate change within affected regions, implying that local production losses could be compensated through intensification and expansion of production elsewhere. However, this requires that site-level actions are integrated into a regional approach to climate change adaptation. We discuss here such a regional approach for cocoa in West Africa, where 70 % of global cocoa supply originates. On the basis of a statistical model of relative climatic suitability calibrated on West African cocoa farming areas and average climate projections for the 2030s and 2050s of, respectively, 15 and 19 Global Circulation Models, we divide the region into three adaptation zones: (i) a little affected zone permitting intensification and/or expansion of cocoa farming; (ii) a moderately affected zone requiring diversification and agronomic adjustments of farming practices; and (iii) a severely affected zone with need for progressive crop change. We argue that for tropical agricultural commodities, larger-scale adaptation planning that attempts to balance production trends across countries and regions could help reduce negative impacts of climate change on regional economies and global commodity supplies, despite the institutional challenges that this integration may pose.     

Iron toxicity resistance strategies in tropical grasses: The role of apoplastic radicular barriers

The revegetation of mined areas poses a great challenge to the iron ore mining industry. The initial recovery process in degraded areas might rely on the use of Fe-resistant grasses. Tropical grasses, such as Paspalum densum and Echinochloa crus-galli, show different resistance strategies to iron toxicity; however, these mechanisms are poorly understood. The Fe-resistance mechanisms and direct iron toxicity as a function of root apex removal were investigated. To achieve this purpose, both grass species were grown for up to 480?hr in a nutrient solution containing 0.019 or 7?mmol/L Fe-EDTA after the root apices had been removed or maintained. Cultivation in the presence of excess iron-induced leaf bronzing and the formation of iron plaque on the root surfaces of both grass species, but was more significant on those plants whose root apex had been removed. Iron accumulation was higher in the roots, but reached phytotoxic levels in the aerial parts as well. It did not hinder the biosynthesis of chloroplastidic pigments. No significant changes in gas exchange and chlorophyll a fluorescence occurred in either grass when their roots were kept intact; the contrary was true for plants with excised root apices. In both studied grasses, the root apoplastic barriers had an important function in the restriction of iron translocation from the root to the aerial plant parts, especially in E. crus-galli. Root apex removal negatively influenced the iron toxicity resistance mechanisms (tolerance in P. densum and avoidance in E. crus-galli).     

Unusual fingerprint patterns in humans: implications for forensic casework and fingerprint research

The Science of Nature - Archosaurs diversified and became dominant during the Mesozoic Era, but their earliest relatives (non-archosaurian archosauromorphs) were already scarcely present in the...