海洋沉积物中细菌DNA和RNA水平群落差异

海洋沉积物中的微生物在生物地球化学循环中具有重要作用.目前,细菌群落的研究多基于16S rRNA基因(DNA)展开,但DNA不仅包括活性微生物DNA也包括非活性微生物DNA,而RNA水平则可表征环境中具有活性的微生物种群.本研究采用荧光定量PCR和Illumina高通量测序技术,在DNA和RNA水平上研究了渤海和南黄海表层沉积物中细菌群落结构.结果表明,细菌DNA基因丰度比RNA基因丰度高1～2个数量级,DNA水平群落多样性高于RNA水平,二者群落结构差异显著.沉积物中的细菌具有活跃的化能异养、硫酸盐还原和硝化作用.基于16S rRNA基因的测序在探索微生物群落功能时可能会误判重要的功能微生物,总细菌群落中的"稀有生物圈"可能包含转录活跃者,发挥着重要的生物地球化学作用.总体而言,在分析来自稳定沉积环境的细菌群落结构时,基于16S rRNA的研究更能反映真实的生态状况.     

东南亚珠芽魔芋多苗接力生长特性及应用前景

以珠芽魔芋人工诱导开花进行规模化无性育种,可将魔芋繁殖系数从1位数提高约330倍;采用催苗技术让种子及叶面球茎提早出苗,可显著延长魔芋生长周期,使魔芋种植周期由3年缩短为1年;魔芋种子1年生长最高膨大率超过5000倍,当年即形成1180g球茎;魔芋叶面球茎最大膨大率超过100倍,两者种植一季魔芋即可用于加工.突破了魔芋繁殖系数低、膨大率低导致种植周期长的双重困局,显著降低了病害风险,大幅度缩短了魔芋种植周期,从而突破魔芋传统种植区域的地理限制,使魔芋总产量超常规增长.     

Simultaneous Feammox and anammox process facilitated by activated carbon as an electron shuttle for autotrophic biological nitrogen removal

• The autotrophic nitrogen removal combining Feammox and Anammox was achieved. • Activated carbon can be used as an electron shuttle to enhance Feammox activity. • Fe(III) was reduced to Fe(II) and the secondary Fe(II) mineral (FeOOH) was obtained. • The iron-reducing bacteria and Anammox consortium was enriched simultaneously. Ferric iron reduction coupled with anaerobic ammonium oxidation (Feammox) is a novel ferric-dependent autotrophic process for biological nitrogen removal (BNR) that has attracted increasing attention due to its low organic carbon requirement. However, extracellular electron transfer limits the nitrogen transformation rate. In this study, activated carbon (AC) was used as an electron shuttle and added into an integrated autotrophic BNR system consisting of Feammox and anammox processes. The nitrogen removal performance, nitrogen transformation pathways and microbial communities were investigated during 194 days of operation. During the stable operational period (days 126–194), the total nitrogen (TN) removal efficiency reached 82.9%±6.8% with a nitrogen removal rate of 0.46±0.04 kg-TN/m³/d. The contributions of the Feammox, anammox and heterotrophic denitrification pathways to TN loss accounted for 7.5%, 89.5% and 3.0%, respectively. Batch experiments showed that AC was more effective in accelerating the Feammox rate than the anammox rate. X-ray photoelectron spectroscopy (XPS) analyses showed the presence of ferric iron (Fe(III)) and ferrous iron (Fe(II)) in secondary minerals. X-ray diffraction (XRD) patterns indicated that secondary iron species were formed on the surface of iron-AC carrier (Fe/AC), and Fe(III) was primarily reduced by ammonium in the Feammox process. The phyla Anaerolineaceae (0.542%) and Candidatus Magasanikbacteria (0.147%) might contribute to the Feammox process, and Candidatus Jettenia (2.10%) and Candidatus Brocadia (1.18%) were the dominative anammox phyla in the bioreactor. Overall, the addition of AC provided an effective way to enhance the autotrophic BNR process by integrating Feammox and anammox.     

区域经济-污染-环境三维评价模型的构建与应用

为深入分析区域环境经济系统变化,在分析经济发展、环境污染、环境质量相互关系的理论基础上,构建了经济发展水平指数、环境污染指数、环境质量指数的三维立方体评价模型,划分了8个块区,分别表达低污染-低质量-低经济发展水平等8种状态,提出了模型的状态评价、发展阶段划分、演变趋势分析功能,以及相对含义、绝对含义评价途径和计算公式.以宁夏银川市为例检验模型,以广州市为目标参照区域进行了相对含义评价,该市1996~2010年内中长时段处于高污染-低质量-低经济发展水平状态,2007年以后转入了高污染-高质量-低经济发展水平,目前处于环境质量趋好、污染压力大、徘徊于环境低质量与高质量"拐点"附近状态.绝对含义评价结果:1996~2010年,该市始终处于高污染-低质量-低经济发展水平.研究表明,因目标参照区域选择和相关国家标准值等主要参数不同,使模型评价具有一定的弹性范围,无量纲的数据处理增强了指数耦合性,评价结果的空间可视化为环境管理决策提供了直接依据,改善了多指标模型评价结果抽象、数据口径不匹配、发展阶段划分不明确等问题,验证了该模型的应用合理性与适应性.     

基于CEEMDAN-SE和LSTM神经网络的PM10浓度预测

针对PM₁₀浓度时间序列具有明显的非线性和波动性特征,提出一种基于自适应噪声的完整集成经验模态分解(complete ensemble empirical mode decomposition with adaptive noise,CEEMDAN)-样本熵(sample entropy,SE)和长短期记忆神经网络(long short-term memory,LSTM)的组合预测模型。首先利用CEEMDAN-SE将原始PM₁₀浓度时间序列分解为若干个复杂度差异明显的子序列;然后针对各子序列的内在特性结合气象因素分别建立适当参数空间的LSTM预测模型;最后将预测结果进行叠加得到最终预测结果。以唐山市4个空气质量监测站的实测PM₁₀浓度数据进行模型验证分析,结果表明:所提预测模型对比其他几种预测模型显示出较高的预测精度,以及良好的普适性。     

园林绿化废弃物资源化利用的贡献度研究——基于减轻北京城市生活垃圾处理压力的视角

园林绿化废弃物是城市固体废弃物的重要构成。为了进一步优化当前园林绿化废弃物的处理方式,引起相关部门和社会公众的重视,借助统计分析理论构建贡献度指数公式,结合生命周期评价等方法围绕园林绿化废弃物资源化利用在资源、经济和环境三方面的贡献度展开量化研究。结果显示,北京市2004—2013年的贡献度指数持续增长,对减轻北京城市生活垃圾处理压力的能力逐年增强,且在改善环境方面的贡献占比超过2/3;对缓解酸化、全球变暖、光化学污染和富营养化有积极作用,在节约稀缺资源如土地空间和能源资源方面的贡献次之,约1/3;在经济方面的贡献最小,但也在一定程度上能够对政府在环境治理方面的投资压力减负。     

粮食产量预测理论、方法与应用Ⅲ.粮食生产潜力中、长期预测理论、模型及其应用

粮食生产潜力中、长期预测的目的是为国家中、长期粮食生产规划提供科学依据。粮食生产潜力中、长期预测的“双向预测理论”：从若干个预测模型中选择出2个模型,一个模型预测的未来产量是持续增加的,体现产量持续增加的科技进步力量;另一个模型预测的未来产量是先增加后减少或持续减少的,体现影响产量持续增加的负面综合因素力量。应用结果表明：模型可预测未来1~10年的粮食生产潜力,平均预测误差在5％以内。大量案例证明粮食生产潜力中、长期预测的“双向预测理论”是科学的、方法是通用的、结果是实用的。     

Exploring spatial change and gravity center movement for ecosystem services value using a spatially explicit ecosystem services value index and gravity model

Spatially explicit ecosystem services valuation and change is a newly developing area of research in the field of ecology. Using the Beijing region as a study area, the authors have developed a spatially explicit ecosystem services value index and implemented this to quantify and spatially differentiate ecosystem services value at 1-km grid resolution. A gravity model was developed to trace spatial change in the total ecosystem services value of the Beijing study area from a holistic point of view. Study results show that the total value of ecosystem services for the study area decreased by 19.75% during the period 1996?C2006 (3,226.2739 US$ × 10⁶ in 1996, 2,589.0321 US$ × 10⁶ in 2006). However, 27.63% of the total area of the Beijing study area increased in ecosystem services value. Spatial differences in ecosystem services values for both 1996 and 2006 are very clear. The center of gravity of total ecosystem services value for the study area moved 32.28 km northwestward over the 10 years due to intensive human intervention taking place in southeast Beijing. The authors suggest that policy-makers should pay greater attention to ecological protection under conditions of rapid socio-economic development and increase the area of green belt in the southeastern part of Beijing.     

火焰原子吸收法测定水中铁的质量控制指标研究

本文研究了火焰原子吸收法测定水中铁的质量控制指标,全国共12个省份的46家实验室参加测定工作,提供了具有全国性指导意义的工作参考数据.研究结果为:标准样品在0.2～4.0mg/L浓度范围内的RSD≤3.0%,RSD'≤10.0%,室间标准偏差≤0.10mg/L;浓度≤2.0mg/L时,RE≤±10.0%,2.0～4.0...     

基于454和Illumina高通量测序平台对长江口邻近海域沉积物微生物群落的比较分析

作为第二代测序技术的主要平台, 454和Illumina测序方法在微生物核酸分析方面有着广泛应用。本研究以16S rRNA基因为标靶, 分别采用454和Illumina测序技术对长江口邻近海域表层沉积物中的微生物DNA进行分析, 通过对序列长度、微生物群落多样性及组成进行比较, 分析两种方法在沉积物微生物群落结构研究方面的适用性。结果表明, Illumina测序获得的序列数和OTU数要多于454, 其中获得的OTUs中以非优势菌群为主。Illumina与454相比能够检出更多微生物菌群, 且检测到的稀有菌群占有较大比例。综上可知, Illumina测序技术在分析微生物群落多样性及物种组成方面要优于454测序技术, 454的长序列优势并未能体现出来, 且454测序技术可能低估了微生物组成及其多样性。