Metagenomic analysis reveals the effects of cotton straw–derived biochar on soil nitrogen transformation in drip-irrigated cotton field

Environmental Science and Pollution Research - Biochar has been widely accepted as a soil amendment to improve nitrogen (N) use efficiency, but the effect of biochar on N transformation metabolic...     

Growth of Zostera japonica in different sediment habitats of the Yellow River estuary in China

Environmental Science and Pollution Research - The estuarine delta of the Yellow River is a region of strong land-ocean-human interactions that undergoes a unique evolutionary process. The delta is...     

不同火灾规模下隧道水幕线性喷水强度的研究

为了探究火源功率和水幕线性喷水强度对烟气特征参数和水幕阻烟隔热能力的影响，以全尺寸隧道为研究对象，采用FDS数值模拟方法，还原验证了前人使用的小尺寸模型，研究了20组工况下烟气特征参数变化的规律。研究结果表明:根据相似性原理还原后的全尺寸模型在相同工况下的模拟结果与小尺寸实验基本一致；水幕系统降低遮光率的效果随线性喷水强度增加而增强，当线性喷水强度增至一定程度时，遮光率和隔热效率无明显变化；对于中、大型规模火灾，水幕有效作用时间出现减少的情况；火源功率为5，20，30 MW的小、中、大规模的隧道火灾，综合考虑经济性和水幕效果，建议分别选择水幕的线性喷水强度为8，14，16 L/(s瘙
簚m)。     

Use of historical and contemporary distribution of mammals in China to inform conservation

A systematic understanding of dynamic animal extinction trajectories for different regions in a nation like China is critically important to developing practical conservation strategies. We explored historical and contemporary changes in terrestrial mammalian diversity to determine how diversity in each of the 5 regions in China has changed over time and to examine the conservation potential of these regions. We used records from databases on Pleistocene mammalian fossils and historical distribution records (1175–2020) for Primates (as a case study) to reconstruct evolutionary and historical distribution trajectories of the 11 orders of terrestrial mammals and to predict their prospective survival based on the national conservation strategy applied. The results indicated that since the Pleistocene, 4–5 mammalian orders have been lost in the northeast, 3 in central China, 2 along the coast, and 1 in the northwest. In the southwest, all 11 orders were maintained. Contemporarily, the coast and southwest had the highest and second-highest species densities. The southwest region and southeastern sections of the northwest region were the most historically and contemporarily diverse areas, which suggests that they should be the first priority for protected area (PA) designation. The central and coastal areas should be secondarily prioritized. In these 2 regions, conservation should focus on human coexistence with nature. Less attention should be paid to the PA in the northeast and western northwest because in these areas ecosystems are depauperate and the climate is harsh. Conservation in these areas should focus principally on avoiding further human encroachment on natural areas. Article impact statement: Historical and contemporary patterns of extinction can be a basis for mammalian conservation strategies.     

Sb release characteristics of the solid waste produced in antimony mining smelting process

Sb release characteristics of blast furnace slag, mining waste rock and tailing sand were investigated in static immersion and dynamic leaching test. These three kinds of waste samples were collected from the antimony mine in Lengshuijiang, China, produced in mining smelting process. Effects of solid/liquid ratio, sample size and pH of leaching solution on Sb release characteristics were inspected based on the analysis of scanning electron microscope, pH and EC of leachate. The optimal parameters for Sb leaching of each sample were analyzed. For blast furnace slag and mining waste rock, Sb release contents increased along with the decline of solid/liquid ratio. The maximum accumulative release contents were 42.13, 34.26 mg/kg at the solid/liquid ratio of 1:20. While Sb release content for tailing sand decreased first and then increased with the reduction of solid/liquid ratio. When the solid/liquid ratio was 1:5, the accumulative Sb release content reached the most (24.30 mg/kg). Sb release content of mining waste rock increased with the drop of leaching solution pH, with the highest accumulative release content of 26.01 mg/kg at pH 2.0. Sb release contents of blast furnace slag and tailing sand showed positive correlation with the variation of leaching solution pH. The maximum accumulative release contents of these two samples were 215.91 and 147.83 mg/kg, respectively, when leaching solution pH was 7.0. In summary, Sb release capacity of the three samples in descending order was tailing sand, blast furnace slag and mining waste rock. pH and EC of the leachate in dynamic test varied independently with the initial pH of leaching solution while showing close relationship with mineral hydrolysis in the waste.     

In situ electron-induced reduction of NOx via CNTs activated by DBD at low temperature

• An in situ electron-induced deNO_x process with CNT activated by DBD was achieved. • Carbon atoms on CNT surface were verified to be excited by plasma in DBD-CNT system. • Reactions between NO_x and excited C result in synergistic effect of DBD-CNT system. In this study, a new in situ electron-induced process is presented with carbon nanotubes (CNTs) as a reduction agent activated by dielectric barrier discharge (DBD) for nitrogen oxide (NO_x) abatement at low temperature (<407 K). Compared with a single DBD system and a DBD system with activated carbon (DBD-AC), a DBD system with carbon nanotubes (DBD-CNT) showed a significant promotion of NO_x removal efficiency and N₂ selectivity. Although the O₂ content was 10%, the NO_x conversion and N₂ selectivity in the DBD-CNT system still reached 64.9% and 81.9% at a specific input energy (SIE) of 1424 J/L, and these values decreased to 16.8%, 31.9% and 43.2%, 62.3% in the single DBD system and the DBD-AC system, respectively. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to investigate surface changes in the CNTs after activation by DBD to explore the NO_x reduction abatement mechanism of this new process. Furthermore, the outlet gas components were also observed via Fourier transform infrared spectroscopy (FTIR) to help reveal the NO_x reduction mechanism. Experimental results verified that carbon atoms excited by DBD and the structure of CNTs contributed to the synergistic activity of the DBD-CNT system. The new deNO_x process was accomplished through in situ heterogenetic reduction reactions between the NO_x and carbon atoms activated by the plasma on the CNTs. In addition, further results indicated that the new deNO_x process exhibited acceptable SO₂ tolerance and water resistance.     

Efficacy of created and restored nesting sites for the conservation of colonial Laridae in the South of France

By rapidly modifying key habitat components, habitat restoration is at risk of producing attractive cues for animals without providing habitats of sufficient quality. As such, individual fitness components, such as reproduction, could be reduced and restored habitats could become ecological traps. This risk notably appears by using artificial constructions in restoration projects, yet few studies have evaluated their efficacy in a robust way. We investigated this by analyzing 154 islets that were created or restored to improve the conservation status of 7 colonial Laridae species in the South of France. From 2007 to 2016, we compared occupancy dynamics and breeding parameters of these species between the restored sites and 846 unmanaged nesting sites. We also explored species’ preference for different nesting site characteristics and their respective effect on breeding parameters. Restored nesting sites were 2–9 times as attractive as unmanaged sites for all species except the Black-headed Gull (Chroicocephalus ridibundus). Colonization probability was up to 100 times higher in sites already used by other species the previous year and increased with distance to the shore until >0.2 when distance was over 250 m. Abandonment probability was 29–70% lower when breeding was successful the previous year in all species except the Sandwich Tern (Thalasseus sandvicensis). Productivity and breeding success probability were 2 times higher on managed sites. Distance from the shore was an important attractive characteristic of artificial nesting sites in all species. Other nesting site characteristics had species-specific effects on colonization, abandonment, and breeding success. Our results indicate that managed nesting sites are successful conservation tools for colonial Laridae in the Mediterranean and do not act as ecological traps. Our study showed that testing the ecological trap hypothesis is a robust way to evaluate the success of restoration projects of breeding habitats.     

排污权交易之排放跟踪数据校核研究

本文以排污权交易的核心业务排放跟踪管理为出发点,选择电厂二氧化硫指标进行排放跟踪数据过程校核体系研究,探索进一步提高排污权交易体系中排放数据准确性的机制。     

中国环境风险现状及发展趋势分析

基于国内2000-2009年以来环境污染事故统计资料,深入分析了中国现阶段环境风险类型、事故高发区域、事故损失、环境风险事故诱因等特征,并对其环境风险演变趋势进行了判断。新时期中国经济增长方式处于转变阶段,以布局型环境隐患和结构型环境风险为首要威胁,风险类型更加复杂化,事故影响范围进一步扩大,由于居民消费转型与科技发展带来的新型环境风险更是不可预知,环境风险压力进一步增大。     

Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn

The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was -0.71 μmol/(m².sec), the ecosytem was a CO₂ sink under soil warming treatment, the lawn ecosystem under the control was a CO₂ source (0.13 μmol/(m².sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q₁₀) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO₂ uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and A_max (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.