浅层地下水升降对菜地土壤剖面硝化/反硝化微生物丰度的影响

为揭示湖泊近岸浅层地下水升降对菜地土壤剖面硝化与反硝化功能微生物基因丰度的影响,以洱海湖滨带菜地土壤剖面为研究对象,通过模拟地下水升降过程,分析了水位升高(S1)、水位降低(S2)及落干(S3)过程中土壤剖面AOA-amoA、AOB-amoA、nirK、nirS、nosZ基因丰度的变化特征,探讨了功能基因与土壤环境因子的耦合关系.结果表明:S3阶段的土壤剖面AOA-amoA和AOB-amoA基因丰度显著高于S1和S2;S1阶段的土壤剖面nirK、nirS、nosZ基因丰度均显著高于S2和S3.AOA-amoA基因丰度显著高于AOB-amoA基因丰度,nirS基因丰度显著高于nirK、nosZ基因丰度;不同取样时期的土壤剖面AOA-amoA、AOB-amoA、nirK、nirS、nosZ基因丰度均表现为A层B层C层D层.水位升降对土壤剖面AOA-amoA、AOB-amoA、nirK、nirS、nosZ基因丰度有显著影响,且AOA-amoA和nirS基因对水位升降更敏感,分别在硝化与反硝化作用中占主导地位;pH、有机碳(SOC)、全氮(TN)为功能基因AOA-amoA、AOB-amoA的环境驱动因子,而功能基因nirK、nirS、nosZ的环境驱动因子为土壤含水量(W)、铵态氮(NH~+_4-N)、硝态氮(NO~-_3-N)、TN、SOC、pH.该研究结果可为揭示浅层地下水升降过程中菜地土壤剖面氮素循环的微生物学机制提供科学依据.     

Influence of carbon sources on nutrient removal in A/O-MBRs: Availability assessment of internal carbon source

Both internal carbon source and some external carbon sources were used to improve the nutrient removal in Anaerobic-Anoxic-Oxic-Membrane Bioreactor (A²/O-MBRs), and their technical and cost analysis was investigated. The experimental results showed that the nutrient removals were improved by all the carbon source additions. The total nitrogen and phosphorus removal efficiency were higher in the experiments with external carbon source additions than that with internal carbon source addition. It was found that pathways of nitrogen and phosphorus transform were different dependent on different carbon source additions by the mass balance analysis. With external carbon source addition, the simultaneous nitrification and denitrification occurred in aerobic zone, and the P-uptake in aerobic phase was evident. Therefore, with addition of C-MHP (internal carbon source produced from sludge pretreatment by microwave-H₂O₂ process), the denitrification and phosphorus-uptake in anoxic zone was notable. Cost analysis showed that the unit nitrogen removal costs were 57.13 CNY/kg N of C-acetate addition and 54.48 CNY/kgN of C-MHP addition, respectively. The results indicated that the C-MHP has a good technical and economic feasibility to substitute external carbon sources partially for nutrient removal.     

糯扎渡自然保护区森林资源碳汇能力评价

利用相关资源调查数据,对属森林生态系统类型的糯扎渡自然保护区的森林资源碳汇量进行了估算,并对保护区的碳汇能力作了初步评价,为保护区管理决策提供科学依据.估算结果表明:糯扎渡自然保护区森林资源碳汇量为741.26×104t,森林和林地的碳汇能力巨大,在碳汇过程中起主体作用.     

有机物料还田对稻田土壤DOM碳源代谢能力的影响

以成都平原典型稻麦轮作长期定位施肥试验土壤为研究对象,设置常规施肥(T1)、猪粪替代50%氮肥(T2)和猪粪替代50%氮肥+秸秆全量还田(T3)这3种处理,采用Biolog-ECO方法,研究长期有机物料还田下土壤和土壤可溶性有机质(DOM)的碳源代谢能力.结果表明,T3处理较T1和T2处理显著增加了土壤的碳源代谢能力,平均颜色变化率(AWCD)分别增长16%和48%;同时T3处理提高了土壤DOM的碳源代谢能力,其AWCD值为0.43.从微生物碳代谢功能多样性指数来看,土壤和土壤DOM中微生物的碳代谢功能多样性指数均以T3处理最高,其中土壤DOM中微生物的Shannon、 Simpson和McIntosh指数分别为2.73、 0.91和3.75.主成分分析和富集分析结果显示,不同施肥处理下土壤和土壤DOM的主要利用碳源类型存在差异,对于DOM而言,T1和T2处理的DOM主要利用碳源仅为糖类,而T3处理增加了对氨基酸类、羧酸类、聚合物类和胺类的利用.土壤pH和质地的改变是引起土壤DOM碳源代谢能力差异的主要因素.综上,猪粪配合秸秆施用显著增加了土壤和土壤DOM的微生物群落多样性和碳源代谢能...     

Preparation and application of efficient TiO2/ACFs photocatalyst

Activated carbon fibers （ACFs） supported titanium dioxide （TiO2） photocatalyst was developed by sol-gel method. The surface morphology and microstructure of the photocatalyst were characterized with scan electron microscope（SEM）, X-ray diffraction patterns and specific surface area analysis. The prepared photocatalyst is specially helpful for the removal of low molecular weight organic pollutants in wastewater. Decomposition efficiency of methylene blue solution by TiO2/ACFs catalyst reached almost 100% under 60 min reaction, while the decomposition efficiency by pure TiO2 was only 25% under 3 h reaction. The mineralization of toluene aqueous solution was measured by total organic carbon instrument, and the evolution of intermediate species was detected by gas chromatograph instrument. The results indicated that the prepared photocatalyst not only enhanced the photoactivity of TiO2, but also suppressed the emergence of intermediate species, which may be more deleterious to human. The enhancement of photocatalysis was due to increased efficiency of adsorption and desorption, which were control steps in heterogeneous photocatalysis.     

广州市城市污泥处理方法

介绍了水泥窑协同处理城市污泥技术、利用城市污泥生产有机肥技术、城市污泥新型压滤机深度脱水技术及污泥改性技术,分析了它们的工艺特点、存在问题、对策及城市污泥处理处置的趋势。认为应当采用多种技术使城市污泥无害化与资源化,在自然界中应建立城市污泥的健康循环,使城市环境可持续发展。     

沿海生态旅游资源评价指标及尺度研究——以江苏沿海为例

旅游资源评价是生态旅游研究的主要内容之一,尺度选取和指标建立是评价的关键。从生态旅游的角度出发,筛选体现沿海湿地类型、生态环境、旅游期望值、海洋文化以及开发程度等项目的一系列指标,综合构建沿海生态旅游资源评价指标体系。运用景观生态学理论,文章提出了沿海生态旅游资源(景观)评价的时空尺度、自然人文理性尺度以及数理统计尺度。在此基础上,运用层次分析法对江苏沿海生态旅游资源的吸引力、开发潜力和综合价值进行定性和定量评价,并探讨了发展江苏沿海生态旅游的策略。     

低丘缓坡开发的生态影响评价研究

土地开发强度大、后备土地资源不足已成为我国部分地区尤其是经济发达地区社会经济发展的重要制约因素,因地制宜开发利用低丘缓坡等未利用土地,有助于缓解城镇建设用地压力,而低丘缓坡开发势必对区域生态系统结构与功能产生重大影响。在分析低丘缓坡开发对生态环境的影响因素与影响方式的基础上,初步提出低丘缓坡开发生态影响评价的程序和方法,为低丘缓坡开发试点工作的生态保护提供技术依据。     

中国环保重点城市API指数的时空模态区域分异

从区域空气污染监测、分析、预报研究与综合管理需求出发,利用经验正交函数EOF方法,将全国47个环保重点城市2004年7月1日～2006年6月30日2年逐日API指数(Air Pollution Index)时空分布资料分解为模态特征向量和时间系数,并对模态间差异性进行了Morlet小波分析,研究其频谱差异.在此基础上,建立了全国环保重点城市API指数时空模态区域分异体系.结果表明:以API指数作为评价指标,中国主要城市空气污染存在明显的区域分异,全国47个重点城市可分为10个区域,分别代表不同的污染时空模态.EOF及Morlet小波方法将全国47个环保重点城市API指数的时空分布清晰地表达出来,为空气污染区域分异研究提供了新的方法与思路.由于城市空间分布稀疏,难以涵盖全国所有城市的空气污染信息,因此,区域划分体系合理性有待进一步验证.     

Organic matter and pH affect the analysis efficiency of P-NMR

Solution ³¹P nuclear magnetic resonance spectroscopy (³¹P-NMR) is a useful method to analyze organic phosphorus (Po), but a general procedure for the analysis method is lacking. The authors used solution ³¹P-NMR, which was found to be an effective method for analysis of Po in Haihe River sediment, to analyze the Po in the surface sediment in Eastern China at the regional scale, and found that the NaOH-ethylenediaminetetraacetic acid (EDTA) extraction rate was affected by environmental factors. At the regional scale, the extraction rate showed a positive relationship with loss on ignition, when the extraction rate was lower than 60%. The extraction rate had no relationship with the loss on ignition when the extraction rate was higher than 60%. The extraction rate showed a negative relationship with pH, which means that the extraction rate was higher in acidic sediment and lower in alkaline sediment. The ratio of TC/TN (the ratio of total carbon to total nitrogen) was considered to represent the origin of organic matter in the sediment. The extraction rate was high when the TC/TN ratio was lower than 20, meanwhile the extraction rate decreased as the TC/TN ratio increased. The results show that the origin of organic matter in sediment significantly affects the NaOH-EDTA extraction rate. This study will give theoretical support for building an effective and general solution ³¹P-NMR analysis method.