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111.
The effect of nutrient and surfactant addition on the biodegradation of phenanthrene was studied in a batch scale soil–slurry system using isolated Mycoplana sp. MVMB2strain. The study was conducted using an artificially phenanthrene spiked and as well as contaminated soil from petrochemical industrial site. Maximum phenanthrene degradation and subsequent high microbial growth were observed at optimum pH (pH 6) and C/N/P ratio (100:20:3). To investigate maximum substrate degradation potential of Mycoplana sp. MVMB2, very high concentrations of phenanthrene (50–200 mg/kg soil) were used. The organism was capable of degrading >60% for a concentration below 20 mg/kg soil and >40% for concentrations up to 200 mg/kg within 8 days. Further the influence of five different surfactants namely Span 80, Tween 20, Triton X‐100, cetyl trimethyl ammonium bromide, and sodium dodecyl sulfate were tested at their critical micelle concentration (CMC) levels for phenanthrene degradation in the soil. The addition of surfactant enhanced the biodegradation and a maximum of 84.49% was obtained for Triton X‐100. Complete phenanthrene degradation by Mycoplana sp. MVMB2 was observed at 3 CMC concentration of Triton X‐100. The optimized parameters obtained were used for the degradation of phenanthrene present in the contaminated soil and 98.6% biodegradation was obtained. Thus, the results obtained in the study suggested that biodegradation of phenanthrene by Mycoplana sp. MVMB2 appeared to be feasible to remediate phenanthrene rich contaminated sites.  相似文献   
112.
针对代表年常规方法的局限性,采用风速年景划分法对风场风资源代表年进行订正。该方法弥补了常规方法的不足,且计算简单,便于应用。  相似文献   
113.
As the product of a variety of sediment sources and sedimentation (and re‐sedimentation) and erosion processes, the geomorphology and sedimentology of carbonate slopes are highly variable. The purpose of this study is to describe sub‐bottom profiles and side‐scan sonar, multibeam and optical data acquired by an autonomous underwater vehicle to explore variability in geomorphological and sedimentological character of the present‐day platform‐marginal, uppermost slope environments (< 240 m water depth) on the north, open‐ocean facing flank of Little Bahama Bank, Bahamas. Although at time scales of greater than 100 ka this margin is progradational, the data illustrate a complex juxtaposition of erosional and depositional processes and features. Erosion is evidenced by two prominent escarpments (70 m and 120 m) that expose eroded, bedded rocky outcrops. These escarpments are interpreted to represent relict features, related to past sea‐level positions, although they still may be shedding debris. Aside from erosional remnants, sedimentation and active transport is indicated by several features, including active bedforms (especially above the 70 m escarpment, but ripples occur to depths of ca 200 m), several mass transport complexes that overlie and cover the lower escarpment, gravity flow deposits and rare slump features. Similarly, a thick (up to 20 m) onlapping sediment wedge, interpreted to be Holocene in age, suggests lateral accretion of the slope by more than 75 m in this period. Data illustrate that this open‐ocean margin is distinct from windward margins in the Bahamas, which typically include near‐vertical walls of erosion or bypass, flanked downdip by rubble and talus, and leeward margins, which have onlapping muddy wedges, but that lack marked terraces or escarpments. Collectively, the results provide perspectives into the nature and controls on complex geomorphological patterns of erosion and deposition in Holocene uppermost slope systems, concepts potentially applicable to ancient analogues.  相似文献   
114.
通过问卷调查,具体分析了吉林省敦化市乡村人群对气候变化趋势和极端冷暖年的感知偏差及人群分异.发现乡村人群对气候变化趋势的感知与科学事实比较符合,由于对变暖转折年代更敏感,因而对变暖的确认度在一些时段与科学事实在变化程度或幅度上存在比较大的偏差.乡村人群对极端冷暖年不如对趋势感知的准确度高.经验积累影响乡村人群对气候变化...  相似文献   
115.
对末次冰消期以来东海内陆架沉积物磁化率的影响因素及其蕴含的古环境信息进行了探讨.对位于浙闽沿岸泥质沉积中心附近的EC2005孔沉积物磁化率、岩性、粒度、常量元素、矿物以及AMS<'14>C测年数据进行了综合分析,得出以下主要结论:EC2005孔沉积物磁化率的变化受多种因素的制约,不同层位的主要控制因素不同,60.20~...  相似文献   
116.
加拿大老年人口状况及发展态势   总被引:1,自引:1,他引:0  
采用加拿大2006年人口普查资料,结合旅居加国的经历,统计分析了加拿大老年人口的发展趋势和现状.分析显示:加拿大老年人口前期(1921-1981年)增长慢,后期(2001—2006年)增长快,老年人口数量中,女性比男性多,寿命比男性长,老年人口分布集中在安大略省;人口老龄化发展过程给社会带来了一系列问题,老龄化使政府和企业的养老负担日益加重,瞻养率大幅度下降,政府每年支付养老金及医疗费用的数量增加,导致劳动力市场压力增大,劳动资源不足.文中还介绍了人口专家为解决加国人口老龄化问题所提出的建议和对策,以及加拿大政府在老年人口养老与医疗方面的一些做法,认为值得中国借鉴.  相似文献   
117.
During Integrated Ocean Drilling Program Expedition 325, 34 holes were drilled along five transects in front of the Great Barrier Reef of Australia, penetrating some 700 m of late Pleistocene reef deposits (post‐glacial; largely 20 to 10 kyr bp ) in water depths of 42 to 127 m. In seven holes, drilled in water depths of 42 to 92 m on three transects, older Pleistocene (older than last glacial maximum, >20 kyr bp ) reef deposits were recovered from lower core sections. In this study, facies, diagenetic features, mineralogy and stable isotope geochemistry of 100 samples from six of the latter holes were investigated and quantified. Lithologies are dominated by grain‐supported textures, and were to a large part deposited in high‐energy, reef or reef slope environments. Quantitative analyses allow 11 microfacies to be defined, including mixed skeletal packstone and grainstone, mudstone‐wackestone, coral packstone, coral grainstone, coralline algal grainstone, coral‐algal packstone, coralline algal packstone, Halimeda grainstone, microbialite and caliche. Microbialites, that are common in cavities of younger, post‐glacial deposits, are rare in pre‐last glacial maximum core sections, possibly due to a lack of open framework suitable for colonization by microbes. In pre‐last glacial maximum deposits of holes M0032A and M0033A (>20 kyr bp ), marine diagenetic features are dominant; samples consist largely of aragonite and high‐magnesium calcite. Holes M0042A and M0057A, which contain the oldest rocks (>169 kyr bp ), are characterized by meteoric diagenesis and samples mostly consist of low‐magnesium calcite. Holes M0042A, M0055A and M0056A (>30 kyr bp ), and a horizon in the upper part of hole M0057A, contain both marine and meteoric diagenetic features. However, only one change from marine to meteoric pore water is recorded in contrast with the changes in diagenetic environment that might be inferred from the sea‐level history. Values of stable isotopes of oxygen and carbon are consistent with these findings. Samples from holes M0032A and M0033A reflect largely positive values (δ18O: ?1 to +1‰ and δ13C: +1 to +4‰), whereas those from holes M0042A and M0057A are negative (δ18O: ?4 to +2‰ and δ13C: ?8 to +2‰). Holes M0055A and M0056A provide intermediate values, with slightly positive δ13C, and negative δ18O values. The type and intensity of meteroric diagenesis appears to have been controlled both by age and depth, i.e. the time available for diagenetic alteration, and reflects the relation between reef deposition and sea‐level change.  相似文献   
118.
浙江省年平均气温百年序列的构建   总被引:1,自引:0,他引:1  
长时间气温序列是气候变化研究的基础,早期气温观测台站的缺乏在某种程度上限制了区域性气温长序列的建立。将局部台站的气温观测值向代表全区水平的气温观测值转化,亦是一种有效利用早期少数气温站点构建区域性气温长序列的重要途径。基于浙江省气温观测台站资料的统计分析,提出了局部台站观测值全局修正(GAoSV)的气温长序列建立方式,并利用该方式构建了浙江省年平均气温百年序列。研究结果表明:省级区域内气温局部台站观测与全区台站观测,两者的气温年值变化具有高度的趋同相关性,所提出的GAoSV气温序列构建方式可在少数气温观测台站的情况下,有效保证全区气温序列的构建可信度,且随着观测台站数量增多,其构建可信度会进一步增大,该方式尤其适合早期气温观测台站稀缺(仅有1~2个)的省市级气温长序列的建立。以GAoSV方式建立的浙江省年平均气温百年序列显示,1905-2012年浙江省年平均气温总体在逐渐升高,增温速率约为0.11℃/10a,1980-2012年期间气温的上升趋势更为明显,增温速率约为0.51℃/10a。  相似文献   
119.
The cartography of land covers was used to study fertility and soil evolution in a mountainous Mediterranean area during the anthropocene period ( Crutzen P J 2002 Geology of mankind Nature 415 23). The aim was to determine changes in fertility as agricultural lands were abandoned in the 14 000 hectare area that constitutes Sant Llorenç del Munt Natural Park in a pre-coastal Catalan mountain range (north-eastern Iberian Peninsula). The analysis of land covers using vegetation maps, orthorectified images and aerial photography has allowed us to differentiate six vegetation groups: holm-oak wood, pine grove, oak wood, scrub, active agricultural fields and abandoned agricultural fields. The anthropic covers over the past 100 years were subdivided into five categories: active fields and those abandoned over four time periods. Study variables include field shape (concave, convex, flat), orientation (north, south) and slope (ranging from 12º to 24º). The parameters used for the physical-chemical soil analysis included organic material, phosphorous and potassium; fertility was classified based on groups, types and classes. The results indicate that even when the visual appearance of certain landscapes is similar, the edaphic characteristics may be very different. Changes induced by human disturbance share this phenomenon. Therefore, land management should be considered globally, taking into account vegetation, soils and water as interdependent factors, since it is their interaction that produces landscape and most affects its evolution over time.  相似文献   
120.
According to the glacial landforms and deposits with the optically stimulated luminescence (OSL) dating results, two glacial stages of the last glacial cycle (LGC) and Late Glacial were identified. The Late Glacial stage (Meteorological Station glacier advance) took place about 11 ka (11.3±1.2 ka), and the last glacial maximum (LGM), named Black Wind Mouth glacier advance, occurred at 20 ka (20.0±2.1 ka). Based on the Ohmura’s formula in which there is a relationship between summer (JJA) atmospheric temperature (T) and the annual precipitation (P) at ELA, the present theoretical equilibrium line altitude (ELAt) in Changbai Mountains was 3380±100 m. Six methods of accumulation–area ratio (AAR), maximum elevation of lateral moraines (MELM), toe–to headwall altitude ratios (THAR), the terminal to summit altitudinal (TSAM), the altitude of cirque floor (CF), and the terminal to average elevation of the catchment area (Hofer) were used for calculation of the former ELAs in different stages. These methods provided the ELA for a range of 2250–2383 m with an average value of 2320±20 m during the LGM, which is 200 m higher than the value of previous investigation. The snowlines during the Late Glacial are 2490 m on northern slope, and 2440 m on western slope. The results show that the snowline on northern slope is 50 m higher than that on western slope during the Late Glacial, and the average snowline is 2465m. The ELA △ values were more than 1000 m during the LGM, and about 920 m lower than now during the Late Glacial stage respectively. Compared with Taiwanese and Japanese mountains in East Asia during the LGM, the effect of the uplift on ELA in Changbai Mountains during the glaciations (i.e. 20 m uplift in the LGM and 11 m in the Late Glacial) is not obvious.  相似文献   
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