生态水利研究的理论基础与重点领域

生态水利是近些年来涌现出的新兴学科研究领域.论文结合国内外相关研究进展和国家重大需求,总结了生态水利的概念内涵和学科发展特点,从系统理论、二元结构和安全边界角度阐释了生态水利研究的理论基础.在此基础上,进一步从水与生态系统的相互作用、水利工程的长期生态效应、河湖连通与湿地水系网络构建、受损生态系统的恢复、生态需水与生态...     

Rethinking the Significance of Reovirus in Water and Wastewater

The genus Orthoreovirus contains nonenveloped viruses with double-stranded gene segments encased in a double-layered icosahedral capsid shell. These features constitute major determinants of virion stability in the environment and virion resistance against physical and chemical agents. Reovirus (ReoV) is the general term most commonly used for all virus strains that infect humans and nonhuman animals. Several studies have demonstrated the frequent occurrence of ReoV in wastewaters and natural waters, including surface and ground waters from different geographical areas. Most of these studies have reported higher concentrations of ReoV than any other enteric virus analyzed. They are more commonly isolated in chlorine-disinfected wastewaters than other enteric viruses, and appear to survive longer in water. The ability of ReoV to form large aggregates, even with different types of enteric viruses (e.g., poliovirus) and their ability to undergo mechanisms of gene segment reassortment among different serotypes may also explain their greater stability. Different approaches have been applied for concentration of ReoV from water; however, the recovery efficiency of the filtration methods has not been fully evaluated. Recently, molecular methods for identification of ReoV strains and quantification of virus genome have been developed. Studies have shown that the overall detection sensitivity of ReoV RNA is enhanced through initial replication of infectious virions in cell culture. More studies are needed to specifically address unresolved issues about the fate and distribution of ReoV in the environment since this virus is not commonly included in virological investigations.     

Characterizing the vegetation community in the provenance slope with high-frequency debris flow北大核心CSCD

In order to explore the characteristics and species diversity of the vegetation growing in the provenance slope with high-frequency debris flow, we selected the slopes on the north and south sides of the valley in the Jiangjiagou watershed as the research object. The structural characteristics and quantitative compositions of the communities of vegetation growing on different positions of the slopes were investigated. The species composition, important value, species diversity, and ground and underground biomass of the different communities on the slope were statistically analyzed, and the correlations of the ground and underground biomass with the diversity were determined. The results showed that: of the total 49 species found, the herbs were the dominant flora, of which 33 were found on the northern slope and 23 were found on the southern slope. There were significant differences in the species composition and composition of the important values along the different positions on the slope, being mainly affected by the pioneer herbaceous plants. We found that Heteropogon contortus, Eulaliopsis binata, Arthraxon hispidus, and Sesbania cannabina were highly adaptable to debris flow. These four species are common to the area and can be used as the main configuration species for future ecological restoration. There were differences in the community characteristics and species diversity at different positions on the slope. For the southern slope of the valley, the Shannon-Wiener diversity index was in the order: stable zone (2.311) > instable zone (2.161) > deposit zone (2.036), and in the order: deposit zone (2.626) > stable zone (1.338) > instable zone (1.057) for the northern slope. There were significant differences in the biomass, being in the order: stable zone > instable zone > deposit zone, with higher values in the northern slope than in the southern slope. Based on the aforementioned results, we suggest that the restoration of vegetation in the area of the provenance slope having high-frequency debris flow should focus on the prevention and protection of the instable zone of the slope by natural processes of recovery. The deposit zone needs rational remediation measures. We should introduce local shrub and arbor to increase the species composition and promote the development of plant communities with vertical structures. © 2018 Science Press. All rights reserved.     

Bacterial community structure of Tricholoma matsutake stipe soil by high-throughput sequencing北大核心CSCD

In order to understand the interaction between microorganisms in soil attached to the stipes of Tricholoma matsutake, we utilized high-throughput sequencing technology using an Illumina HiSeq 2500 System (San Diego, CA, USA) to explore the bacterial community structure in such soils and analyzed the effects of microorganisms on the formation and growth of T. matsutake. A total of 6 730 sequences were obtained from the samples, and these sequences were clustered into 928 operational taxonomic units (OTUs) at a 97% similarity level. In addition, these OTUs were grouped into 22 bacterial phyla (including 62 classes, 90 orders, 162 families, and 275 genera) and 2 archaeal phyla (including 4 classes, 6 orders, 7 families, and 8 genera). Proteobacteria was the dominant phylum present in all the samples, and these bacteria were significantly more abundant in soils attached to stipe of T. matsutake than they were in the control samples. Similarly, Beta-proteobacteria were the dominant class, and bacteria in this class were less abundant than they were in the control samples. Moreover, the genus Burkholderia within the Proteobacteria was more abundant in the control samples than in the T. matsutake soil samples. Generally, Proteobacteria, especially the genus Burkholderia, played an important role in the growth of T. matsutake, whereas other bacteria, such as Unknown-Ellin 60, would probably inhibit the growth of T. matsutake. This study showed that bacteria might be involved in the growth of T. matsutake and the formation of its fruiting bodies, but they had no positive relationship with bacterial abundance, which may provide theoretical guidance for the cultivation of T. matsutake. © 2018 Science Press. All rights reserved.     

Acute toxicity of three avermectins to anuran tadpoles北大核心CSCD

Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are among the most effective agricultural pesticides and antiparasitic agents. In this report, three avermectins (abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB) were used to assess their toxic effects on tadpoles of four anuran species (Duttaphrynus melanostictus, Hylarana guentheri, Polypedates megacephalus and Microhyla heymonsi) using a static-renewal acute toxicity test. The results showed that there were significant dose-responsive correlations between the accumulated dead probit of tadpoles and the concentrations of the three avermectins. The 96-h half lethal concentrations (LC50) of ABM to the tadpoles of the four species were 0.042, 0.034, 0.020, and 0.014 mg/L; the 96-h LC50 values of IVM were 0.029, 0.012, 0.012, and 0.006 mg/L, and the values of EMB were 0.118, 0.111, 0.122, and 0.089 mg/L, respectively. Our study reveals that these agrochemicals probably make a significant contribution to the decline of amphibian populations, and provides valuable information about the toxic effects of avermectins on amphibians. © 2018 Science Press. All rights reserved.     

Isolation,identification, culture conditions,and laccase production of white rot fungus北大核心CSCD

The white rot fungi are members of Basidiomycota, which can degrade lignin and form white rot. They are high producers of extracellular laccases. In the present study, pure culture strain of high-temperature and high-laccase production types (numbered as BUA-01) was isolated from the fruiting bodies of a white rot fungus collected in the campus of Beijing University of Agriculture. The taxonomic characteristic was determined based on morphological and ITS sequence analysis. Furthermore, the optimal culture conditions for the mycelia were determined, including carbon source, nitrogen source, C/N ratio, growth factors, temperature, and pH. Extracellular laccase production was investigated in liquid fermentation with different concentrations of Cu (CuSO4) as inducer. Decolorizing activity of the fermentation broth was assayed using three azo dyes: Evans blue, methyl orange, and eriochrome black T. The results showed that the strain possessed the highest homology toward Trametes hirsuta, with the homology ratio of 100% and the genetic distance of 0, suggesting that the strain BUA-01 belonged to the genus Trametes. The culture condition investigated revealed that the optimal condition for mycelia growth included the following: carbon source, starch; nitrogen source, soybean powder and yeast extract; C/N ratio, 40/1 and 10/1; temperature, 37 °C; and pH, 6.0-7.0. The assayed growth factors had no significant effect on mycelial growth. It demonstrated high laccase activity in liquid fermentation. The highest extracellular laccase activity of 1 081.33 ± 6.3 U/mL was observed in the broth with a Cu adjunction concentration of 0.25 mmol/L after a 96-h culture period. It was about 26-fold higher than that of the control group. The isolated strain exhibited significant decolorizing activity toward the azo dyes Evans blue, methyl orange, and eriochrome black T, with the decolorization rate at 12 h of 93.31% ± 0.16%, 92.37% ± 0.42%, 79.25% ± 0.64%, respectively. This suggests that the strain possesses potential applications in laccase production and dye degradation. © 2018 Science Press. All rights reserved.     

Isolation,identification, and biological characteristics of a wild Chaga mushroom北大核心CSCD

In this study, a pure culture strain (numbered as F1501) was obtained using tissue separation and purification methods from the sclerotia of Chaga mushroom from Russia. Further researches included studies on classification, optimum growth conditions of mycelia, extracellular polysaccharides from fermentation broth and their antioxidant activity, and artificial acclimation. According to the identification of the internal transcribed spacer (ITS) region, it was confirmed that F1501 was a species of the genus Inonotus and family Hymenochaetaceae, which had 99% similarity with Inonotus obliquus. F1501 was further classified as I. obliquus based on the morphological characteristics of its mycelia and sclerotia. The optimal carbon source, nitrogen source, C/N ratio, growth factor, temperature, and pH value for the growth of the F1501 strain mycelia were maltose, beef extracts, 10/1, B2, 28 °C, and 8.0, respectively. Liquid fermentation of F1501 was performed using PD media and a 10% inoculation amount at 28 °C and 150 r/min for 7 d. The content of polysaccharides in the fermentation broth was 476.32 mg/L, with a total antioxidant activity of 0.19 mmol/L (Trolox) and hydroxyl free radical-scavenging activity of 72.7%. Artificial acclimation study revealed that the fruiting body-like structure was obtained using cottonseed hulls as the main substrate. In the present study, a new strain of I. obliquus and its biological characteristics were explored, which could provide a theoretical basis for the artificial acclimation and development of wild mushrooms. © 2018 Science Press. All rights reserved.     

Effects of precipitation and temperature on rain-use efficiency of China's forests北大核心CSCD

Water plays an important role in the growth of plants. It is important to investigate the responses of different ecosystems to precipitation patterns, especially in terms of global changes involving extreme precipitation or drought. However, little is known about the rain-use efficiency (RUE) in China's forests and the correlation of the RUE with the precipitation and other environmental factors. Furthermore, it is unclear whether differences in the forest types or functional groups result in divergent RUE patterns. To investigate the RUE in China's forests, we analyzed the data from 1 266 sampling plots from 17 forest types. The results indicated that: (1) the mean RUE of China's forests is 1.21 g m-2 mm-1. The RUE and precipitation are negatively correlated in all the 17 forest types; (2) the average RUE of broadleaved forests (mainly angiosperms) is higher than that of coniferous forests (mainly gymnosperms), and the angiosperms are more adaptable to changes in the precipitation than gymnosperms; (3) the average RUE of deciduous forests is higher than that of the evergreen forests. The RUE of deciduous forests declines with increasing precipitation to a threshold value. However, the RUE of evergreen forests are unaffected by changes in the precipitation; and (4) the latitude and mean annual temperature are the major factors constraining the RUE under comprehensive environmental factors. We conclude that the mean RUE declines with increasing precipitation to a threshold value, and that the temperature is a crucial factor for RUE. © 2018 Science Press. All rights reserved.     

细颗粒物(PM_(2.5))主要组分模拟溶液对发光细菌的光抑制分析

为明确NH_4~+、 NO_3~-、SO_4~(2-)及金属等组分在水溶性提取液对发光细菌的光抑制过程中所起的作用,参照PM_(2.5)样品提取液浓度,模拟配制与3级以上PM_(2.5)样品提取液中主要组分:硫酸盐、硝酸盐、氨盐相同浓度的溶液,同时选取与PM_(2.5)可溶性提取液发光抑制率相关性较强的铅、锌,配制不同浓度级别模拟溶液,测试各单一组分对发光细菌的发光抑制率及其混合溶液对发光细菌的联合影响效应。基于毒性单位法(TU)、相加指数法(AI)和混合毒性指数法(MTI)评价了混合体系联合影响的作用类型。结果表明,与3~6级PM_(2.5)可溶性提取液中硫酸氨、硫酸氢氨、硝酸氨、硫酸锌和硝酸铅浓度相同的模拟溶液对发光细菌的发光没有抑制作用。不同的评价方法对PM_(2.5)主要组分混合体系联合效应评价结果具有较好的一致性,硫酸氨、硝酸氨、硫酸氢氨混合溶液中,对发光细菌的光抑制均为硫酸氢氨的独立作用,硫酸锌与硝酸铅的混合体系,锌和铅对发光细菌的联合影响效应表现为协同,硫酸氨、硝酸氨、硫酸氢氨与硫酸锌、硝酸铅的多元混合体系呈现协同作用。     

Photolysis and photooxidation of typical gaseous VOCs by UV Irradiation: Removal performance and mechanisms

UV photodegradation of 27 typical VOCs was systematically investigated. Contribution of photolysis and photooxidation to VOCs removal was identified. Gaseous VOC could be partially converted to particles by 185/254 nm UV irradiation. The mineralization and conversion of 27 VOCs by UV irradiation were reported. Photodegradation by ultraviolet irradiation (UV) is increasingly applied in volatile organic compound (VOC) and odor gas treatments. In this study, 27 typical VOCs, including 11 hydrocarbons and 16 hydrocarbon derivatives, at 150–200 ppm in air and nitrogen gas were treated by a laboratory-scale UV reactor with 185/254 nm irradiation to systematically investigate their removal and conversion by UV irradiation. For the tested 27 VOCs, the VOC removal efficiencies in air were within the range of 13%–97% (with an average of 80%) at a retention time of 53 s, which showed a moderate positive correlation with the molecular weight of the VOCs (R = 0.53). The respective contributions of photolysis and photooxidation to VOC removal were identified for each VOC. According to the CO₂ results, the mineralization rate of the tested VOCs was within the range of 9%–90%, with an average of 41% and were negatively correlated to the molecular weight (R = -0.63). Many of the tested VOCs exhibited high concentration particulate matters in the off-gases with a 3–283 mg/m³ PM₁₀ range and a 2–40 mg/m³ PM_2.5 range. The carbon balance of each VOC during UV irradiation was analyzed based on the VOC, CO₂ and PM₁₀ concentrations. Certain organic intermediates and 23–218 ppm ozone were also identified in the off-gases. Although the UV technique exhibited a high VOC removal efficiency, its drawbacks, specifically low mineralization, particulate matters production, and ozone emission, must be considered prior to its application in VOC gas treatments.