Spatial and temporal dynamics of bacterial contamination in South France coastal rivers: focus on in‐stream processes during low flows and floods

Faecal indicator bacteria (thermotolerant coliform and faecal streptococci) were enumerated in a Mediterranean coastal river to evaluate bacterial contamination levels in relation to hydrological conditions, to estimate delivery of bacterial loads to transitional and coastal waters (Thau lagoon) and to identify bacterial sources of pollution and their contribution to the bacterial flow. Results showed that (1) in low flow conditions, mean bacterial concentrations were higher than EU guidelines for bathing waters; (2) floods had higher concentrations of indicator bacteria than low flows; (3) low flow conditions represented a negligible proportion of bacterial loads compared with high flow and flood periods; (4) during medium and low flow conditions, bacteria were stored in riverbed fine sediments forming in‐stream stores that may be flushed during floods; (5) the first flush effect was highlighted during an early autumn flood as was the role of in‐stream stores during the course of the flood; and (6) point sources that continuously feed the river are contributing to the pool of bacteria accumulated in the riverbed sediment. Copyright © 2013 John Wiley & Sons, Ltd.     

深海微生物培养模拟平台温度控制技术研究

针对深海微生物培养系统对温度条件的苛刻要求,在分析系统构成及建模的基础上,介绍了一种对系统的两级滞后环节采用了PI控制和双Smith预估反馈的方法,通过内环和外环Smith预估控制,精确的消除了温度控制系统中滞后延迟环节的影响,提高了PI控制强度,减少了超调,提高了系统动态响应和稳态精度。在系统Matlab仿真和实际实验中得到了良好的效果,满足系统的精度要求。     

活性氧化镁−微生物固化黄土试验研究

以活性氧化镁和微生物共同作用固化的黄土试样为研究对象,通过含水率、无侧限抗压强度、X射线衍射（XRD）和扫描电镜（SEM）等试验,研究了活性氧化镁掺量、养护龄期和初始含水率对固化试样含水率、无侧限抗压强度、固化产物和微观结构等的影响。结果表明：固化试样含水率随氧化镁掺量增加和养护龄期增长而降低;无侧限抗压强度随活性氧化镁掺量（5%～20%）增加而增大,随龄期发展总体上不断增大,但当氧化镁掺量为10%和15%时,后期强度稍有降低;当氧化镁掺量为5%和10%时,无侧限抗压强度随初始含水率增加而减小,而当氧化镁掺量为15%和20%时,无侧限抗压强度随初始含水率增加先增大后减小。XRD和SEM结果显示,随着氧化镁掺量增加,水化后未进一步反应的氢氧化镁越多;反应生成的水合碳酸镁具有膨胀性和胶结性,对土颗粒间缝隙进行填充,并将土颗粒胶结在一起。     

美国蒙大拿州冰川国家公园冰缘条带形地表植物功能属性和土壤微生物随坡位变化（英文）

The retreating snowfields and glaciers of Glacier National Park, Montana, USA, present alpine plants with changes in habitat and hydrology. The adjacent and relic periglacial patterned ground consists of solifluction terraces of green, vegetation-rich stripes alternating with sparsely vegetated brown stripes. We established georeferenced transects on striped periglacial patterned ground for long-term monitoring and data collection on species distribution and plant functional traits at Siyeh Pass and at Piegan Pass at Glacier National Park. We documented species distribution and calculated the relative percent cover(RPC) of qualitative functional traits and used 16 S rRNA from soil samples to characterize microbial distribution on green and brown stripes. Plant species distribution varied significantly and there were key differences in microbial distribution between the green and brown stripes. The rare arctic-alpine plants Draba macounii, Papaver pygmaeum, and Sagina nivalis were restricted to brown stripes, where the RPC of xeromorphic taprooted species was significantly higher at the leading edge of the Siyeh Pass snowfield. Brown stripes had a higher percentage of the thermophilic bacteria Thermacetogenium and Thermoflavimicrobium. Green stripes were co-dominated by the adventitiously-rooted dwarf shrubs Salix arctica and the possibly N-fixing Dryas octopetala. Green stripes were inhabited by Krummholz and seedlings of Abies lasiocarpa and Pinus albicaulus. Prosthecobacter, a hydrophilic bacterial genus, was more abundant on the green stripes, which had 6,524 bacterial sequences in comparison to the 1,183 sequences from the brown stripes. While further research can determine which functional traits are critical for these plants, knowledge of the current distribution of plant species and their functional traits can be used in predictive models of the responses of alpine plants to disappearing snowfields and glaciers. This research is important in conservation of rare arctic-alpine species on periglacial patterned ground.     

东海,黄海测区的空气微生物研究

对东海、黄海的近岸、远岸海区空气中陆源性和海洋性微生物含量进行了测定。并比较了不同测区间空气微生物含量的差别,分析了它们的昼夜变化状态,以及气温对这些变化的影响。认为测区空气微生物状态指示海洋与陆地、人类活动及环境污染与海洋空气间的相互作用。     

西双版纳热带山地利用过程中的土壤退化

土壤养分和土壤微生物生长代谢水平的衰退是热带山地退化的重要表现形式。二者的变化基本是一致的。即从热带雨林→33a次生林→6a轮歇地→4a轮歇地→旱谷地→橡胶林→荒草坡呈降低趋势；相对于热带雨林而言，不同利用方式土壤微生物和土壤养分状况均有不同程度的下降，且随退化程度增高减幅增大，土壤微生物衰减的速率比土壤养分的衰减更快。说明山地的退化严重影响着土壤微生物的生长代谢水平以及它们之间的协同作用，从而影响土壤碳氮循环代谢途径。降低土壤肥力水平。     

Sterols as markers of sewage contamination in a tropical urban estuary (Guanabara Bay, Brazil): space–time variations

Guanabara Bay, located adjacent to Rio de Janeiro in Brazil, is highly contaminated by substances derived from domestic and industrial effluents as well as from agricultural runoff. In the present work, sedimentary coprostanol and other faecal sterols were used to investigate historical trends in sewage contamination. Sediment cores were collected from eight different (and characterized) locations in the bay and were sectioned into dated segments. Organic carbon was determined by dry combustion and sterols were separated and quantified by GC/MS. The space-distribution of organic carbon and faecal sterol concentrations generally coincided with the presence of known pollution sources. Concentrations of coprostanol as high as 40 μg g⁻¹ were found, indicating areas of severe sewage contamination. Faecal sterol ratios, commonly used as tools to investigate contamination in temperate environments, however, were found to have limited applicability to this tropical estuarine system, probably due to the influence of intensive primary production and microbial processes.     

The Diatom Nitzschia sicula (Castr.) Hust. and Naupliar Faecal Minipellets in the Adriatic sea

Abstract. Nitzschia sicula (C astr .) H ust ., a planktonic pennate diatom, dominated the microphytoplankton (10⁴-5 times 10⁴ cells. 1^-1) in the central, oligotrophic Southern Adriatic Pit waters (20-50m layer) in May 1990. Nauplii dominated the microzooplankton (3 indiv. 1^-1in the 0-50m layer, 130 μm mean body length) and produced a considerable amount of faecal (mini)pellets (1900. 1^-1 at 50m, mean diameter 47μm), which were compactly filled with N. sicula frustules. The subsurface accumulation of diatoms and nauplii was probably the result of both productive activity under specific hydrographic conditions and the convergence in a relatively strong southern Adriatic cyclonic gyre; the advective transport of populations along the shear zone, at the boundary between water masses of different thermo-haline characteristics may also have played a role. The amount of minipellets was high if compared with the data available from other seas. This was probably due to high production of minipellets, their slow sinking rate, and/or an absence of manipulation of the faecal material by zooplankton.     

以大洋钻探开展冲绳海槽热液活动研究的建议

关于沟弧盆构造体系下的海底热液活动,因涉及的问题繁多,一直是海洋地质学界十分注目的重要研究课题。相比之下,西太平洋沟弧盆体系的马里亚纳海槽和西南太平洋的汤加－斐济海盆中的劳海盆都有ＤＳＤＰ／ＯＤＰ的支撑,有关海底热液活动及其构造属性、地壳类型、形成时代等已有了十分明确的结论,唯冲绳海槽至今尚未有此机会。为了迎接１９９８年大洋钻探船来西太平洋海域,特建议在冲绳海槽设站钻探,可在地理座标２７°１５′～２７°３５′Ｎ,１２６°５６′～１２７°１０′Ｅ的范围、水深１３００～１５５０ｍ水域内海底热液活动活跃区选站,连续钻探４～５孔,其目的拟解决以下４个问题：１．冲绳海槽现代海底热液活动通道在岩层中的最大透过深度及其岩石学性质;２．冲绳海槽的热液类型和成岩成矿作用;３．热液活动与地壳性质;４．热液活动在沟弧盆体系演化中的意义。     

冰冻圈微生物学：回顾与展望

冰冻圈是地球上的负温圈层。冰冻圈各个要素中生存的微生物是地球上生命多样性的重要组分,对这些生命体及其生长繁殖和起源演化规律的揭示,不仅极大地丰富着生命科学和冰冻圈科学,还为深入了解全球变化和地外生命提供重要线索。冰冻圈微生物学的发展也将造福于人类。在回顾冰冻圈微生物研究的基础上,提出冰冻圈微生物学的概念,为冰冻圈科学和微生物学发展提供新视角。