Phylogenetic diversity of planktonic bacteria in the Chukchi Borderland region in summer

Planktonic bacteria are abundant in the Chukchi Borderland region. However, little is known about their diversity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization (FISH) showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic (AAP) bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria (Alpha, Beta and Gamma subclasses), Bacteroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone libraries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro-teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.     

Nitrogen budget of the eelgrass, Zostera marina in a bay system on the south coast of Korea

Above- and below-ground productivities and tissue N content were measured monthly to quantify N incorporation to sustain eelgrass growth in Koje Bay on the south coast of Korea from January to December 2002. N acquisition was also estimated through measurements of N uptake kinetics, tissue biomass, and in situ inorganic N concentrations in water column and sediments. Above- and below-ground productivities were highest in summer and lowest in late fall and winter. Leaf tissue N content was highest in December and lowest in July, while rhizome tissue N content was highest in October and lowest in April. Estimated monthly N incorporation by leaf tissues based on the leaf productivity and N content ranged from 0.4 g N m^?2 month^?1 in November to 2.0 g N m^?2 month^?1 in May. N incorporation by below-ground tissues ranged from 0.1 g N m^?2 month^?1 in February to 0.2 g N m^?2 month^?1 in October. Annual whole plant N incorporation was 14.5 g N m^?2 y^?1, and N incorporation by leaf tissues accounted for about 87 % of total N incorporation. Maximum uptake rate (V _max ) and half saturation constant (K _m ) of leaf NH₄ ⁺ uptake were significantly lower than those of root NH₄ ⁺ uptake. Above- and below-ground biomass ranged from 20.8 g DW m^?2 and 8.6 g DW m^?2 in winter to 350.0 g DW m^?2 and 81.3 g DW m^?2 in spring, respectively. NH₄ ⁺ concentrations varied from 0.2 to 4.3 mM in water column and from 93.0 to 551.7 mM in sediment pore water. Based on these measurements, annual N acquisition by root tissues contributed slightly higher than that by leaf tissues to total plant N acquisition. During winter, monthly leaf N acquisition was lower than monthly leaf N incorporation. This implies that Z. marina has internal nitrogen retention system to offset the shortage and excess of nitrogen.     

绿洲和戈壁近地面层热量和物质输送特征对比

利用甘肃金塔绿洲和戈壁10 m涡旋相关法的观测资料对比研究温度、湿度和二氧化碳浓度(CO₂)的平流和湍流通量特征.结果表明,在典型绿洲-戈壁复杂下垫面上,热量和物质的平流通量比湍流通量的值大1到2个量级;在绿洲和戈壁,受平流输送影响和下垫面强迫,不同性质标量湍流的水平和垂直通量分布具有不同的特征.     

Estimation of non-CO2 GHGs emissions by analyzing burn severity in the Samcheok fire, South Korea

This study was performed to estimate the emission of non-CO 2 greenhouse gases(GHGs) from biomass burning at a large fire area.The extended methodology adopted the IPCC Guidelines(2003) equation for use on data from the Samcheok forest fire gathered using 30 m resolution Landsat TM satellite imagery,digital forest type maps,and growing stock information per hectare by forest type in 1999.Normalized burn ratio(NBR) technique was employed to analyze the area and severity of the Samcheok forest fire that occurred in 2000.The differences between NBR from pre-and post-fire datasets are examined to determine the extent and degree of change detected from burning.The results of burn severity analysis by dNBR of the Samcheok forest fire area revealed that a total of 16,200 ha of forest were burned.The proportion of the area characterized by a ’Low’ burn severity(dNBR below 152) was 35%,with ’Moderate’(dNBR 153-190) and ’High’(dNBR 191-255) areas were at 33% and 32%,respectively.The combustion efficiency for burn severity was calculated as 0.43 for crown fire where burn severity was ’High’,as 0.40 for ’Moderate’ severity,and 0.15 for ’Low’ severity surface fire.The emission factors for estimating non-CO 2 GHGs were separately applied to CO 130,CH 4 9,NO x 0.7 and N 2 O 0.11.Non-CO 2 GHGs emissions from biomass burning in the Samcheok forest fire area were estimated to be CO 44.100,CH 4 3.053,NO x 0.238 and N 2 O 0.038 Gg.     

Temporal trend, spatial distribution, and terrestrial sources of PBDEs and PCBs in Masan Bay, Korea

Congener specific determination of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) was carried out in 21 surface sediment samples and a sediment core from Masan Bay, Korea. Among the 40 PBDE congeners targeted only 29 were detectable. PBDE congener profile within sediments was dominated by BDE-209 followed by BDEs-99, -47, -153 and -183, sequentially. In surface sediments, the average ΣPBDEs levels approached that of average ΣPCBs values. However, trends observed in the sediment core suggest that this pattern will alter over time and result in higher surface sediment PBDE concentrations than PCBs in future. Various diffuse and point sources for PBDEs and PCBs were identified in this location. Shipping and other industrial activities were associated with PCB contamination while domestic and industrial waste discharges corresponded with PBDE contamination. The average concentration for PBDEs and PCBs in surface sediments were 5.7, 7.2 ng/g dry weight, respectively.     

决策树在遥感影像分类中的应用

在充分了解决策二叉树分类过程的基础上, 以西藏波密地区的TM遥感影像为研究对象, 提取并分析各种典型地物的反射光谱特征, 利用不同地物的光谱差异并结合人工目视判读建立了一组能够精确、快速划分遥感影像的分类规则。用ENVI建立分类决策树对实验区遥感影像进行分类, 并将分类结果和传统的最大似然法相比较。结果表明:决策树分类的总体精度和Kappa分别为97.15%和0.9644, 优于传统的最大似然法, 取得了较为满意的分类结果。      

地应力影响煤层气勘探开发的研究现状与展望

通过总结评述前人关于地应力影响煤层气勘探开发的相关文献和成果,讨论了地应力与煤层气成藏、地应力与煤储层渗透率、地应力与煤储层压裂改造、地应力与煤层气井位部署的关系,对相关研究工作的未来走势进行了展望。认为：地应力控制着煤层气成藏过程中的各个环节,是影响煤层渗透率中最主要的因素,也是煤层气井压裂设计和井网部署必须考虑的重要参数。地应力研究对煤层气勘探开发意义重大,且亟待加强。     

上派河大桥控制爆破拆除的施工实践

运用控制爆破技术,成功完成对悬臂钢筋混凝土斜拉桥爆破拆除,其布孔、装药、防护等方面为同类工程提供了参考作用。     

Verification and validation of a seismic response analysis code for framed structures using the ASI‐Gauss technique

In this report, the capabilities of the adaptively shifted integration (ASI)‐Gauss code in the analysis of the seismic responses of framed structures are verified and validated by comparing the results with detailed numerical simulations performed by the parallel finite element analysis code, E‐Simulator, and with experimental results obtained by E‐Defense. The numerical results obtained by both codes showed good agreement with the experimental results obtained by E‐Defense. Furthermore, seismic waves with unnaturally large magnitudes are applied to a high‐rise building model to demonstrate the ability of the ASI‐Gauss code to analyze the collapse behaviors of building frames. Copyright © 2013 John Wiley & Sons, Ltd.     

蜀南地区二叠系茅口组古岩溶地区水系分布及岩溶地貌单元特征*

蜀南地区茅口组为一套沉积稳定的巨厚层生物碎屑灰岩,基质致密性脆。中二叠世末的东吴运动使蜀南地区茅口组顶部发育古风化壳岩溶,古岩溶地区水系控制着古岩溶的发育和演化。在研究古地貌恢复方法的基础上,分析研究区地层特征和区域构造背景,采用印模法进行古地貌恢复,进而研究了古岩溶地区的水系发育特征。在此基础上,结合风化壳表面侵蚀溶蚀特征、沉积物性质、地貌组合形态、钻井和地震资料,把研究区划分为岩溶台地、岩溶陡坡、岩溶缓坡及岩溶盆地4种二级地貌单元和溶丘洼地、岩溶槽谷、峰林平原等10种三级地貌单元,进一步分析了各种地貌单元的岩溶特征,为下一步的储集层预测提供了有利的目标。