生物炭对土壤酶活和细菌群落的影响及其作用机制

生物炭因其独特的理化性质能够提高土壤碳氮矿化速率及改善土壤微生态环境,因此探索生物炭调控土壤微生态环境与土壤酶活及其作用机制对改善土壤质量具有重要意义.采用大田试验方式研究不同生物炭施用水平0（CK2）、0.6（T1）、0.9（T2）、1.2（T3）和1.5（T4）t·hm^-2以及完全空白对照（CK1：不施任何肥料和生物炭）对土壤养分、土壤酶活和细菌群落结构的影响.结果表明,生物炭施用后土壤容重降低,pH值、速效磷、速效钾、有机质含量和碳氮比均升高,较CK2处理提高的范围分别为0.32%~5.83%、14.09%~23.16%、0%~38.70%、7.49%~14.16%和4.06%~10.13%.随着生物炭用量的增加,4个土壤酶活性均呈现先升高后降低的趋势;蔗糖酶（INV）、脲酶（URE）、过氧化氢酶（CAT）和中性磷酸酶（NPH）分别较CK2处理提高的范围为63.73%~166.37%、117.52%~174.03%、12.98%~23.59%和60.84%~119.71%.与此相对应的细菌多样性显著提升,尤其是增加了芽单胞菌门（Gemmatimonadetes）和变形菌门（Proteobacteria）等促生菌的丰度;减少酸杆菌门（Acidobacteria）、放线菌门（Actinobacteria）的丰度.相关性分析表明土壤碳氮比是影响土壤酶活性的关键因素,且土壤酶活又与细菌多样性存在显著的正相关关系;上述4种土壤酶活与芽单胞菌门（Gemmatimonadetes）的相对丰度呈现极显著正相关关系（P<0.01）,其中CAT是影响细菌群落结构的关键因子.本研究揭示了生物炭对土壤酶活及微生物菌落影响作用机制,为生物炭调控土壤酶体系和微生态生物学环境提供了理论依据.     

青藏高原拉萨河流域附石藻类群落结构特征及其驱动因子分析

为探究拉萨河中下游流域附石藻类群落结构特征及其驱动因子,于2019年9月采集并鉴定附石藻类,分析了附石藻类物种组成及空间分布状况,并采用冗余分析识别了影响附石藻类群落的关键环境因子.结果表明,共计鉴定出附石藻类6门31属,附石藻类平均细胞密度为1.92×10⁶ cells·m^-2,其中硅藻门种类数和细胞密度在各采样点均最大;干、支流附石藻类种类数和细胞密度差异显著.干、支流的优势藻属差异较小,干流的主要优势属有硅藻门异极藻（Gomphonema）、脆杆藻（Fragilaria）、桥弯藻（Cymbella）和蓝藻门浮鞘丝藻（Planktolyngbya）,支流的主要优势属有硅藻门异极藻（Gomphonema）、脆杆藻（Fragilaria）、桥弯藻（Cymbella）和蓝藻门颤藻（Oscillatoria）.冗余分析表明,温度、pH和溶解氧是影响干流附石藻类优势属群落结构的主要驱动因子,HCO₃^-和流速是影响支流附石藻类优势属群落结构的主要驱动因子.本研究为拉萨河中下游流域水生生态系统保护及水质管理提供基础资料和理论依据.     

Effect of nitrobenzene on the performance and bacterial community in an expanded granular sludge bed reactor treating high-sulfate organic wastewater

Less than 50 mg/L nitrobenzene brought little effect on anaerobic sulfate reduction. Kinetics of sulfate reduction under different nitrobenzene contents was studied. Increased nitrobenzene contents greatly changed the bacterial community structure. Genus Desulfovibrio played the key role in anaerobic sulfate reduction process. Nitrobenzene (NB) is frequently found in wastewaters containing sulfate and may affect biological sulfate reduction process, but information is limited on the responses of sulfate reduction efficiency and microbial community to the increased NB contents. In this study, a laboratory-scale expanded granular sludge bed reactor was operated continuously to treat high-sulfate organic wastewater with increased NB contents. Results successfully demonstrated that the presence of more than 50 mg/L NB depressed sulfate reduction and such inhibition was partly reversible. Bath experiments showed that the maximum specific desulfuration activity (SDA) decreased from 135.80 mg SO₄^2?/gVSS/d to 30.78 mg SO₄^2?/gVSS/d when the NB contents increased from none to 400 mg/L. High-throughput sequencing showed that NB also greatly affected bacterial community structure. Bacteroidetes dominated in the bioreactor. The abundance of Proteobacteria increased with NB addition while Firmicutes presented an opposite trend. Proteobacteria gradually replaced Firmicutes for the dominance in response to the increase of influent NB concentrations. The genus Desulfovibrio was the dominant sulfate-reducing bacteria (SRB) with absence or presence of NB, but was inhibited under high content of NB. The results provided better understanding for the biological sulfate reduction under NB stress.     

新疆博格达山北坡表土花粉散布特征

基于博格达山北坡68个表土样品花粉组合特征,对比植物群落样方调查结果,借助聚类分析、主成分分析方法,探讨了表土花粉组合与现代植被分布的关系。研究表明,(1)博格达山北坡表土花粉可划归5个不同植被带,湿度是影响其分布的主要因素,藜科(Chenopodiaceae)、蒿属(Artemisia)、云杉属(Picea)花粉分布受气流影响显著,忽略它们对其他植被带花粉组合的干扰,表土花粉与现代植被分布对应良好。各植被带均有其特有的花粉组合方式,山地荒漠带藜科-蒿属组合占绝对优势,山地草原带演替为蒿属-藜科-禾本科(Poaceae)-蔷薇科(Rosaceae)组合,山地森林带以云杉属-桦木属(Betula)-蒿属-藜科-禾本科为主,高山草甸带以蒿属-云杉属-藜科-莎草科(Cyperaceae)组合为特征,高山垫状植被带表现为蒿属-藜科-蔷薇科-云杉属组合。(2)草本植物花粉含量(62.7%)优势明显,乔、灌木(37.3%)次之。蒿属(23.1%)、藜科(21.5%)、云杉属(18.1%)、莎草科(9.4%)、禾本科(8.6%)、桦木属(5.7%)、蔷薇科(5.3%)等科(属)含量高、变幅大,为最主要的花粉类型,可作为古气候研究的重要依据,藜科、蒿属产量大、易传播,表现出超代表性,云杉属代表性较好,莎草科则受自身结构及保存条件等多重因素影响呈低代表性。(3)蒿属/藜科(A/C)比值不仅能将山地荒漠带、山地草原带区分开,还能指示研究区域湿度变化,古环境重建时可作为区域有效湿度的代用指标。     

Feasibility of weeds-based compost-cultivated Agaricus bisporus北大核心CSCD

Making full use of local weed resources to produce Agaricus bisporus is of great importance in reducing production costs and protecting the environment. In this paper, three trial experiments were conducted on the basis of weed diversity investigation around the Miyun Reservoir and the adjustment of formulation and technology in the industrial production of A. bisporus. Compost samples from different phases of the composting process and at various cultivation stages were collected for the determination of their physical-chemical properties, lignocellulose content, lignocellulolytic enzyme activities, and bacterial communities enrichment by 16S rRNA gene sequencing. The yield of mushrooms in each different trial was also calculated. The results showed several types of reservoir weeds with high, thick and hard stems. The saturated moisture of weeds was 76.78% after baling. The water content, carbon content, and C/N ratio of the samples decreased gradually during composting, but had little change during cultivation. The nitrogen content decreased at the end of phase I and increased at the end of phase II. During composting, the loss rates of hemicellulose and cellulose were both between 40% and 60%, and the loss rate of lignin was between 20% and 30%. During cultivation, instead, the loss rate of lignin was between 16% and 21%. The changes in the content of cellulose and hemicellulose of compost were consistent with that of the activity of the related degradation enzymes. A total of 432 595 valid sequences were obtained by Illumina sequencing for the samples derived from the three composting trials, and the average length of the sequences was 441 bp. Taxonomic analysis showed that the dominant bacteria were Prevotella (phylum Bacteroidetes), Bacillus (phylum Firmicutes), Thermus, Truepera, and Caldicoprobacter (phylum Deinococcus-Thermus), Thermopolyspora (phylum Actinobacteria), and Pseudoxanthomonas (phylum Proteobacteria). The yield of the three trials was in the range of 17.1-19.7 kg/m2. It is thus feasible to use reservoir weeds compost instead of wheat straw compost for the cultivation of A. bisporus. © 2018 Science Press. All rights reserved.     

Bacterial community structure in waterlogged bamboo slips excavated from the Laoguanshan Han Dynasty Tomb of Chengdu北大核心CSCD

To investigate the bacterial community structure features of soak solutions used to preserve bamboo slips that were excavated from Han dynasty tomb located in Laoguanshan of Chengdu and to reveal the diversity of bacteria in these soak solutions, PCR-DGGE was employed. Subsequently, the major DGGE bands were excised and sequenced to analyze the phylogeny of bacteria. The richness (S), Shannon-Wiener index (H), and Simpson index (D) of deionized water (0#) without the soaked bamboo slips were higher than those of the other samples. Among the bamboo slip soak solution samples, there were significant differences in these indicators; the bacterial genetic diversity of sample 121# was the highest and that of sample 1# was the lowest. Principal Component Analysis (PCA) showed that there were comparatively large differences among the samples, and the similarity between sample 1# and others was the lowest. Based on the sequence analysis, the major community of bacteria in soak solution were belonged to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, including Cupriavidus, Aquabacterium, Comamonas, Albidiferax, Hyphomicrobiaceae, Azospirillum, Nevskia, Streptococcus, Staphylococcus, Sediminibacterium, and Propionibacterium, among which Cupriavidus of the β-Proteobacteria class was detected in all samples. The bacterial community structure of the soak solutions that were collected from different bamboo slips was quite complex and significantly different. The analysis of the main bacterial community revealed the potential bacteria species that may trigger the damage in bamboo slips; the result provided a reference to prevent waterlogged bamboo slips from microbial diseases in the future. © 2018 Science Press. All rights reserved.     

Investigate of in situ sludge reduction in sequencing batch biofilm reactor: Performances,mechanisms and comparison of different carriers

Biofilm is an effective simultaneous denitrification and in situ sludge reduction system, and the characteristics of different biofilm carrier have important implications for biofilm growth and in situ sludge reduction. In this study, the performance and mechanism of in situ sludge reduction were compared between FSC-SBBR and SC-SBBR with constructed by composite floating spherical carriers (FSC) and multi-faceted polyethylene suspension carriers (SC), respectively. The variation of EPS concentration indicated that the biofilm formation of FSC was faster than SC. Compared with SCSBBR, the FSC-SBBR yielded 0.16 g MLSS/g COD, almost 27.27% less sludge. The average removal rates of COD and NH₄⁺-N were 93.39% and 96.66%, respectively, which were 5.21% and 1.43% higher than the average removal rate of SC-SBBR. Investigation of the mechanisms of sludge reduction revealed that, energy uncoupling metabolism and sludge decay were the main factors for sludge reduction inducing 43.13% and 49.65% less sludge, respectively, in FSC-SBBR. EEM fluorescence spectroscopy and SUVA analysis showed that the hydrolytic capacity of biofilm attached in FSC was stronger than those of SC, and the hydrolysis of EPS released more DOM contributed to lysis-cryptic growth metabolism. In additional, Bacteroidetes and Mizugakiibacter associated with sludge reduction were the dominant phylum and genus in FCS-SBBR. Thus, the effect of simultaneous in situ sludge reduction and pollutant removal in FSC-SBBR was better.

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Microbial community dynamics at high organic loading rates revealed by pyrosequencing during sugar refinery wastewater treatment in a UASB reactor

High strength sugar refinery wastewater was treated in a mesophilic UASB. Pyrosequencing reveals microbial community succession with OLR increase. Diversity of microbial communities in OLR12 is much higher than those in OLR36 and OLR54.0 kgCOD/(kg VSS·d). Fermentative bacteria could deal with increasing OLR through the increase of microbial diversity and quantity. Hydrogen-producing acotogens and methanogens mainly coped with high OLR shocks by increasing the quantity of community The performance and microbial community structure in an upflow anaerobic sludge blanket reactor (UASB) treating sugar refinery wastewater were investigated. The chemical oxygen demand (COD) removal reached above 92.0% at organic loading rates (OLRs) of 12.0–54.0 kgCOD/(m³·d). The volatile fatty acids (VFAs) in effluent were increased to 451.1 mg/L from 147.9 mg/L and the specific methane production rate improved by 1.2–2.2-fold as the OLR increased. The evolution of microbial communities in anaerobic sludge at three different OLRs was investigated using pyrosequencing. Operational taxonomic units (OTUs) at a 3% distance were 353, 337 and 233 for OLR12, OLR36 and OLR54, respectively. When the OLR was increased to 54.0 kgCOD /(m³·d) from 12.0 kgCOD/(m³·d) by stepwise, the microbial community structure were changed significantly. Five genera (Bacteroides, Trichococcus, Chryseobacterium, Longilinea and Aerococcus) were the dominant fermentative bacteria at the OLR 12.0 kgCOD/(m³·d). However, the sample of OLR36 was dominated by Lactococcus, Trichococcus, Anaeroarcus and Veillonella. At the last stage (OLR= 54.0 kgCOD/(m³·d)), the diversity and percentage of fermentative bacteria were markedly increased. Apart from fermentative bacteria, an obvious shift was observed in hydrogen-producing acetogens and non-acetotrophic methanogens as OLR increased. Syntrophobacter, Geobacter and Methanomethylovorans were the dominant hydrogen-producing acetogens and methylotrophic methanogens in the samples of OLR12 and OLR36. When the OLR was increased to 54.0 kgCOD/(m³·d), the main hydrogen-producing acetogens and hydrogenotrophic methanogens were substituted with Desulfovibrio and Methanospirillum. However, the composition of acetotrophic methanogens (Methanosaeta) was relatively stable during the whole operation period of the UASB reactor.     

From disaster to development: a systematic review of community‐driven humanitarian logistics

A plethora of untapped resources exist within disaster‐affected communities that can be used to address relief and development concerns. A systematic review of the literature relating to community participation in humanitarian logistics activities revealed that communities are able to form ad hoc networks that have the ability to meet a wide range of disaster management needs. These structures, characterised as Collaborative Aid Networks (CANs), have demonstrated efficient logistical capabilities exclusive of humanitarian organisations. This study proposes that CANs, as a result of their unique characteristics, present alternatives to established humanitarian approaches to logistics, while also mitigating the challenges commonly faced by traditional humanitarian organisations. Furthermore, CANs offer a more holistic, long‐term approach to disaster management, owing to their impact on development through their involvement in humanitarian logistics. This research provides the foundation for further theoretical analysis of effective and efficient disaster management, and details opportunities for policy and practice.     

典型气田土壤铁还原活性与微生物群落关系研究

由微生物驱动的土壤铁还原过程在铁的生物地球化学循环中起到重要作用,该过程还可与土壤重金属的转化及石油烃类有机污染物的降解等过程相偶联.油气田土壤常具有潜在有机污染物风险,本研究以重庆涪陵页岩气田的土壤（潜在烃类有机物污染风险）为对象,测定土壤铁还原活性（Iron Reducing Potential,IRP）,并利用Illumina Miseq测序解析其中的铁还原微生物类群,进而探讨IRP、土壤基本性质及微生物群落之间的关系.结果表明,该区域土壤铁还原菌群的优势菌门为厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）和拟杆菌门（Bacteroidetes）.与低IRP样品相比,高IRP样品中Pseudomonas、norank Peptococcaceae及Lentimicrobium等菌属具有较高的相对丰度.基于各样品OTU （Operational Taxonomic Unit）组成的PCoA （Principal Co-ordinates Analysis）分析表明,高、中及低IRP样品中铁还原菌群落结构差异显著（R²=0.25,p<0.01）,且一些分别属于Acetoanaerobium、Proteiniphilum、Petrimonas、Tessaracoccus及Exiguobacterium菌属中的OTUs在高IRP样品中显著上调.结构方程模型表明,铁还原微生物的群落结构是直接决定土壤IRP的主要因子,土壤氨氮及有效磷均可通过影响微生物群落结构来间接影响IRP,且氨氮还可通过直接影响有效磷来间接影响土壤IRP.本研究揭示了影响典型页岩气田土壤铁还原活性的关键因子及微生物机制,为进一步深入研究铁还原条件下土壤有机污染物去除的微生物机制打下基础.