总量控制约束下区域用水结构调控策略及动态模拟

在既定水资源供给下,通过调控区域用水结构,提高用水效率与效益,使经济社会发展与用水总量限制的水资源约束相适应,是目前区域经济社会发展面临与亟待解答的关键科学问题。选择若干指标定量描述用水系统与社会经济系统耦合关系的基础上,以国民经济部门划分和用水主体划分相结合的方式,细化第一、二、三产业、生活和生态用水指标,建立了江苏省用水结构与产业结构、用水需求与经济社会发展指标互动反馈的模拟调控的系统动力学模型。在对当前发展模式下的江苏省用水总量发展趋势模拟预测分析基础上,选择对系统影响显著的参数作为调控变量,设计了5种对比情景,动态模拟水资源供求变化和用水结构变化情况,提出了江苏省用水总量控制下用水结构调控方案和对策,为区域落实最严格水资源管理制度提供决策依据。     

长年耕作对北方旱作麦田土壤细菌群落结构及理化性质的影响

为探究旱作麦田长期耕作对不同土层细菌群落结构的影响及其与土壤理化性质的关系,于2016~2021年在山西农业大学闻喜旱地小麦试验示范基地开展长期定位试验,研究夏闲期免耕（NT）、深松（ST）和深翻（DP）这3种耕作方式对不同土层土壤理化性质,细菌群落α、β多样性,细菌门和属优势物种及差异物种的影响,并采用PICRUSt2预测其代谢功能.结果表明,旱作麦田连续5a深松和深翻较免耕显著提高了20~40 cm土层土壤含水量,显著降低了0~20 cm土层土壤有机碳含量;深松较深翻显著提高了0~20 cm土层土壤含水量、土壤有机碳、可溶性有机碳和可溶性有机氮含量.深松和深翻较免耕可提高0~40 cm土层土壤细菌群落的α多样性,且深松高于深翻.深松和深翻较免耕显著提高了0~20 cm土层中酸杆菌门、硝化螺旋菌门和20~40 cm土层中酸杆菌门、绿弯菌门、芽单胞菌门、Rokubacteria门、GAL15门和硝化螺旋菌门的相对丰度;显著提高了0~20 cm土层硝化螺旋菌属和20~40 cm土层Rubrobacter属和链霉菌属的相对丰度.深松较深翻显著提高了0~40 cm土层酸杆菌门、芽单胞菌门的相对丰度.冗余分析表明,0~20 cm土层的土壤有机碳、可溶性有机碳和可溶性有机氮含量对放线菌门和牙殖球菌属产生正向效应,且深松下0~40 cm土层的土壤含水量对酸杆菌门、绿弯菌门和芽单胞菌门产生正向效应.PICRUSt2预测结果表明,深松和深翻较免耕显著提高了20~40 cm土层细菌群落的氨基酸代谢和辅酶维生素代谢的相对丰度,但降低了脂质代谢的相对丰度;深松较深翻显著提高了0~40 cm土层细菌群落的氨基酸代谢和0~20 cm土层其他氨基酸代谢的相对丰度.总之,旱地麦田夏闲期深松或深翻均可提高土壤含水量、土壤细菌群落的α多样性及细菌群落的代谢能力,深松还可提高酸杆菌门和芽单胞菌门的相对丰度,并提高细菌群落的氨基酸代谢能力,从而提高了土壤可溶性有机碳、氮含量.     

密云水库入库河流微生物群落演替对氮素形态转化的影响

密云水库是北京市重要的地表饮用水源地,但近年来,密云水库库区及入库河流中的总氮（TN）浓度呈现连年上升的趋势.以密云水库上游典型入库河流牤牛河为例,考察各形态氮素变化的空间分布规律,并从微生物群落组成和功能预测的视角,解析氮素形态的转化,以期为密云水库的氮污染治理提供科学依据.结果表明,密云水库上游除TN外,其余水质理化指标均满足我国地表水环境质量标准（GB 3838-2002）的Ⅱ类标准.入库河流TN浓度显著高于库区（P<0.05）,且以NO₃^--N为主,占比为77.7%~92.9%.半城子水库库区的C/N较高,有助于反硝化脱氮的发生,表现出一定自净能力.牤牛河水体和底质中微生物群落结构具有显著差异,呈现一定的空间分布特征,高NO₃^--N浓度是影响微生物群落结构演替的主要环境因子.牤牛河中存在大量硝化和反硝化功能微生物,反硝化菌相对丰度高于硝化菌,且均呈现出底质略高于水体的特点.牤牛河优势硝化菌和反硝化菌分别为Nitrosopumilus和Pseudomonas.PICRUSt2功能预测结果表明,牤牛河微生物氮代谢以NO₃^--N还原模块为主,且主要发生于水体中;硝化过程的功能基因在水体中的丰度最高,主要为narGH;而参与NO₃^--N还原反应的主要功能基因为底质中的异养反硝化菌（DNRA）所携带的nirBD,而反硝化模块的功能基因主要为nirK.     

杭州市产业结构与环境污染间的灰色关联度分析研究

文章运用灰色关联分析方法,分别以经济发展指标GDP和环境污染指标废气、废水和固废排放量为参考序列,以产业发展经济数据为比较序列,进行灰色关联度分析,结果发现,杭州现有产业结构初步适应了经济与环境相协调的发展理念,但是有些部门产业或行业仍对环境的污染产生着重要影响。     

Abundance and diversity of ammonia-oxidizing archaea in response to various habitats in Pearl River Delta of China, a subtropical maritime zone

Ammonia-oxidizing archaea (AOA) are widely considered key to ammonia oxidation in various environments. However, little work has been conducted to simultaneously investigate the abundance and diversity of AOA as well as correlations between archaeal amoA genotypes and environmental parameters of different ecosystems at one district. To understand the abundance, diversity, and distribution of AOA in Pearl River Delta of China in response to various habitats, the archaeal amoA genes in soil, marine, river, lake, hot spring and wastewater treatment plant (WWTP) samples were investigated using real-time fluorescent quantitative PCR and clone libraries. Our analyses indicated that the diversity of AOA in various habitats was different and could be clustered into five major clades, i.e., estuary sediment, marine water/sediment, soil, hot spring and Cluster 1. Phylogenetic analyses revealed that the structure of AOA communities in similar ecological habitats exhibited strong relation. The canonical correspondence method indicated that the AOA community structure was strongly correlated to temperature, pH, total organic carbon, total nitrogen and dissolved oxygen variables. Assessing AOA amoA gene copy numbers, ranging from 6.84×10⁶ to 9.45×10⁷ copies/g in dry soil/sediment, and 6.06×10⁶ to 2.41×10⁷ copies/L in water samples, were higher than ammonia-oxidizing bacteria (AOB) by 1-2 orders of magnitude. However, AOA amoA copy numbers were much lower than AOB in WWTP activated sludge samples. Overall, these studies suggested that AOA may be a major contributor to ammonia oxidation in natural habitats but play a minor role in highly aerated activated sludge. The result also showed the ratio of AOA to AOB amoA gene abundance was positively correlated with temperature and less correlated with other environmental parameters. New data from our study provide increasing evidence for the relative abundance and diversity of ammonia-oxidizing archaea in the global nitrogen cycle.     

Absolute dominance of hydrogenotrophic methanogens in full-scale anaerobic sewage sludge digesters

Anaerobic digestion （AD） is gaining increasing attention due to the ability to covert organic pollutants into energy-rich biogas and, accordingly, growing interest is paid to the microbial ecology of AD systems. Despite extensive efforts, AD microbial ecology is still limitedly understood, especially due to the lack of quantitative information on the structures and dynamics of AD microbial communities. Such knowledge gap is particularly pronounced in sewage sludge AD processes although treating sewage sludge is among the major practical applications of AD. Therefore, we examined the microbial communities in three full-scale sewage sludge digesters using qualitative and quantitative molecular techniques in combination： denaturing gradient gel electrophoresis （DGGE） and real-time polymerase chain reaction （PCR）. Eight out of eleven bacterial sequences retrieved from the DGGE analysis were not affiliated to any known species while all eleven archaeal sequences were assigned to known methanogen species. Quantitative real-time PCR analysis revealed that, based on the 16S rRNA gene abundance, the hydrogenotrophic order Methanomicrobiales is the most dominant methanogen group （〉 94% of the total methanogen population） in all digesters. This corresponds well to the prevailing occurrence of the DGGE bands related to Methanolinea and Methanospirillum, both belonging to the order Methanomicrobiales, in all sludge samples. It is therefore suggested that hydrogenotrophic methanogens, especially Methanomicrobiales strains, are likely the major players responsible for biogas production in the digesters studied. Our observation is contrary to the conventional understanding that aceticlastic methanogens generally dominate methanogen communities in stable AD environments, suggesting the need for further studies on the dominance relationship in various AD systems.     

腐蚀损伤对典型铝合金结构疲劳寿命的影响研究

目的研究严酷服役条件下飞机结构的寿命衰减问题。方法以飞机关键结构模拟件为研究对象,基于编制的某机场环境加速试验谱进行当量加速腐蚀试验,采用MTS810材料试验系统进行预腐蚀后的疲劳试验。结果通过对试验结果的分析,确定了关键结构疲劳寿命腐蚀影响系数与腐蚀损伤尺寸之间的对应关系。结论关键结构腐蚀损伤宽度与疲劳寿命腐蚀影响系数相关性最好。     

芦芽山华北落叶松林土壤剖面细菌群落分布格局

微生物群落是维持森林土壤生态系统结构和功能的关键组分.细菌群落在土壤剖面上的垂直分布对森林土壤碳库和土壤营养循环具有重要影响.利用Illumina MiSeq高通量测序技术,分析了芦芽山华北落叶松(Larix principis-rupprechtii)林腐殖质层及0～80 cm土层细菌群落特征,探究影响土壤剖面细菌群落结构的驱动机制.结果表明,细菌群落的α多样性随土壤深度的增加显著单调降低,群落结构在土壤剖面上有显著差异.放线菌门(Actinobacteria)、变形菌门(Proteobacteria)的相对丰度随着土壤深度增加而降低;酸杆菌门(Acidobacteria)和绿弯菌门(Chloroflexi)的相对丰度随土层深度的增加而增加.RDA分析结果表明,土壤NH⁺₄、 TC、 TS、 WCS、 pH、 NO^-₃和TP是决定土壤剖面细菌群落结构的重要因子,其中pH的影响最为显著.分子生态网络分析表明,凋落物层和亚表层土壤(10～20 cm)细菌群落的复杂性较高,深层(40～80 cm)土壤细...     

土地利用结构与空间格局对鄱阳湖流域中小河流水质的影响

为揭示土地利用结构与空间格局对中小河流水质的影响机制,于2022年1月与2022年7月在鄱阳湖流域3条中小河流的25个采样点收集水样.采用Bioenv分析、Mantel检验与方差分解量化不同空间尺度的土地利用结构与空间格局对水质的影响,使用广义加性模型拟合水质与土地利用结构与空间格局的关系,广义线性模型构建分段回归模型,并基于逐步递归法计算阈值.结果表明：①土地利用结构与空间格局对河流水质的平均解释率在丰水期（59.72%）大于枯水期（48.95%）;子流域与河岸100 m是土地利用结构与空间格局影响中小河流水质的关键尺度,平均解释率分别为54.70%和64.88%;土地利用结构与空间格局的共同解释部分是驱动河流水质变化的重要因素,占总解释率的66.90%.②土地利用结构对中小河流水质的影响具有显著的阈值效应,当子流域尺度下建设用地占比低于2%、耕地占比低于8%和林地占比高于82%,河岸缓冲区尺度下建设用地占比低于12%、耕地占比低于41%和林地占比高于49%时,均能明显改善水质.③空间格局对中小河流水质的影响也具有阈值效应但弱于土地利用结构,当子流域尺度下斑块形状值大于28.77和斑块多样性大于0.69,河岸缓冲区尺度下斑块形状值大于2.99和斑块多样性大于1.02时,均能改善水质.以上结果表明,加强对子流域与河岸100 m尺度的土地利用的管理,合理规划土地利用结构与空间格局能够有效地防止水质恶化.     

近地面层湍流通量输送相似性及相干结构特征

利用2018年广东省环珠江口气候环境与空气质量变化野外科学观测研究站70 m气象塔上涡动协方差系统连续观测资料,对不同大气稳定度条件下近地面层相干结构的统计特征及其对湍流通量相似性的影响进行了初步研究.结果表明：(1)无量纲风速标准差(稳定、不稳定)和气温标准差(不稳定)遵循莫宁-奥布霍夫相似理论;(2)湍流速度(u、v、w)谱、温度(T)谱、CO₂和H₂O浓度谱在惯性副区均满足-2/3定律.w-T协谱、垂直速度(w)与标量(CO₂、H₂O)浓度的协谱(w-CO₂、w-H₂O)在惯性副区遵循-4/3定律;(3)不稳定条件下,热力湍流对H₂O和CO₂标量具有很好的输送作用,而以动量通量输送为代表的机械作用在弱不稳定条件下对H₂O和CO₂的输送效果最好;(4)上冲和下扫运动对湍流通量输送起主导作用,且随湍涡尺度的变化略有差异,湍流通量输送对大气层结的依赖性较弱.