Distribution of the indigenous microorganisms and mechanisms of their orientational activation in Daqing Oilfield

The distribution of indigenous microorganisms was surveyed in Block 1 of Daqing Oilfield. Based on this survey, the indigenous microorganisms in the formation water were activated with different activator systems at the simulated stratum ecological environment. The changes of the number of bacteria of various physiological groups were determined during the process of activation. Also changes of pH value and composition of gas productions were analyzed at the end of culturing. The results showed that the selected block formation water contained a great number of saprophytic bacteria, hydrocarbon-oxidizing bacteria, fermentative bacteria, methane-producing bacteria and sulfate-reducing bacteria. Under the conditions that the growth of sulfate-reducing bacteria was controlled the block had the potential to enhance oil recovery by activating beneficial bacteria. The growth of sulfate-reducing bacteria can be inhibited through the activation of nitrate-reducing bacteria. The number of nitrate-reducing bacteria reached 10⁶–10⁷ cells/mL, but sulfate-reducing bacteria reached only 0–45 cells/mL in A system. Methane-producing bacteria can be activated by C, D activators. The relative content of biological methane in the light hydrocarbon gas reached 80% in C, D systems. B activator was conducive to the propagation of acid-producing bacteria, so that the pH value of the culture medium decreased from 7.5 to around 5.0. Hydrocarbon-oxidizing bacteria can be activated by various activator systems. There was low molecular light hydrocarbon in gas production according to the analysis of gas chromatograph. According to the content of methane and the number of methane-producing bacteria, methane only can be generated through activating methane-producing bacteria. By choosing different activator systems, various populations of indigenous microorganisms can be activated accordingly.     

2014 IGU Regional Conference held in Krakow,Poland

The 2014 Regional Conference of the International Geographical Union（IGU）was held on August 18-22 in Krakow,Poland.The total number of participants was 1374 from 64 countries and regions,including 357 from Poland.Germany,Japan,Czech,UK,China,Russia,USA,France and Hungary are the top countries of attendees in this conference.     

河西走廊最近一次强沙尘暴的调查分析

1996年5月29~31日在甘肃河西走廊又出现了一次强沙尘暴天气。从这次强沙尘暴和1993年"5·5"强沙尘暴的比较分析可知,春季在河西走廊周围易形成以沙漠为中心的高温低压区,与西西伯利亚向东南方向移动的高压冷气流形成明显的气压梯度,这就是大风的动力源。大风前期,在气温、压温比等方面有明显的预兆,由此可进行强沙尘暴的预测预报。     

Denitrification potential of marsh soils in two natural saline-alkaline wetlands

Little information is available on denitrification potential of marsh soils in natural saline-alkaline wetlands. The denitrification potentials of an open wetland in the floodplain(Erbaifangzi wetland) and a closed wetland(Fulaowenpao wetland) in backwater areas in Jilin Province of Northeast China were monitored by an anaerobic incubation at 30℃ for 25 days. Our results showed that the relative denitrification index(RDI) increased gradually with incubation time, and showed a rapid increase in the first 5 days of incubation. The RDI values declined quickly from surface soils to subsurface soils and then kept a small change in deeper soils along soil profiles over the incubation time. Denitrification proceeded much faster in the top 20 cm soils of open wetland than in the closed wetland, whereas no significant differences in RDI values were observed in deeper soils between both wetlands. The RDIs were significantly negatively correlated with bulk density and sand content, while a significantly positive correlation with clay content, soil organic matter, total nitrogen and phosphorous. The maximum net NO–3-N loss through denitrification in 1 m depth were higher in the open wetland than the closed wetland with higher soil pH values. Future research should be focused on understanding the influencing mechanisms of soil alkalinity.     

The influence of rainfall and land use patterns on soil erosion in multi-scale watersheds: A case study in the hilly and gully area on the Loess Plateau,China

Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau (LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use (LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different- scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor (R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor (C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.     

祁连山中部亚高山草地作物系数估算

利用Lysimeter蒸散仪于2011-2014年对祁连山中部黑河上游天涝池流域亚高山草地实际蒸散量进行观测。用FAO Penman-Monteith模型对草地参考蒸散量进行估算,根据草地植被高度结合气象数据,以估算日尺度作物系数,以估算的作物系数与模拟的参考蒸散量计算草地实际蒸散量,并用观测值进行验证。结果表明：FAO改进后的作物系数计算方法适合该区域草地作物系数的计算;以FAO Penman-Monteith模型估算的日蒸散量为0.50~7.26 mm,生长季日均蒸散量有年际变化,2011年 > 2014年 > 2012年 > 2013年。总体来看,土壤蒸发总量年际变化不大,影响蒸散量年际变化的主要部分是植被的蒸腾。     

Influencing factors of seed long-distance dispersal on a fragmented forest landscape on Changbai Mountains,China

Seed long-distance dispersal(LDD) events are typically rare, but are important in the population processes that determine large-scale forest changes and the persistence of species in fragmented landscapes. However, previous studies focused on species dispersed via animal-mediated LDD, and ignored those dispersed by wind. The aim of this study was to assess the effects of canopy openness, edge, seed source, and patch tree density on the LDD of seeds by wind in forest. We collected birch seeds, a typical wind-dispersed species, throughout a larch plantation. We then assessed the relationship between birch LDD and each factor that may influence LDD of seeds by wind including distance to edge, canopy openness size, distance to mature forest, and the tree density of the larch plantation. We used univariate linear regression analysis to assess the influence of those factors on birch LDD, and partial correlations to calculate the contribution of each factor to LDD. The results showed that both canopy openness and edge had significant influences on birch LDD. Specifically, a negative relationship was observed between distance to edge and birch LDD, whereas there was a positive correlation between canopy openness size and LDD. In contrast, the distance to the mature forest was not correlated with birch LDD. Our results suggest that patch tree density could potently affect the probability of LDD by wind vectors, which provides novel and revealing insights regarding the effect of fragmentation on wind dynamics. The data also provide compelling evidence for the previously undocumented effect of habitat fragmentation on wind-dispersed organisms. As such, these observations will facilitate reasonable conservation planning, which requires a detailed understanding of the mechanisms by which patch properties hamper the delivery of seeds of wind-dispersed plants to fragmented areas.     

广州市制造业与生产性服务业协同集聚与空间相似性

基于企业微观大数据,从空间相似性的视角,运用核密度法、双变量空间自相关法和地理探测器等分析方法,对广州市6个制造行业和5个生产性服务行业的空间协同关系展开分析,在街镇尺度下从行业层面探讨生产性服务业与制造业在城市内部的协同集聚.研究发现:行业集聚中心的空间布局形态显示,广州的制造业与生产性服务业布局具有空间相似性.制造...     

历史背景认知对殖民遗产旅游情感体验的影响 ——以广州沙面岛为例

中国数量众多的租界本质是殖民统治时期的空间遗存,但随着时间的推移,一些历史背景已经被遗忘。以广州沙面为例,利用情感量表问卷对具备不同历史知识的340个样本进行认知与情感体验评价,探索历史背景认知对旅游者情感体验的作用与情感体验差异的产生原因。研究发现：1）愉悦、目标一致性与新奇/确定决定积极情感,自我投入决定消极情感;2）接受沙面历史背景介绍的旅游者情感体验更消极,认知评价具有显著差异。殖民历史背景认知通过降低旅游者的愉悦、目标一致性,减弱积极情感欢乐、喜爱,提升自我投入从而增强消极情感气愤、悲伤、畏惧;3）殖民历史认知是否导致情感体验趋于消极由个体的评价所决定。历史背景知识为旅游者带来深入旅游体验的同时不会影响旅游追求愉悦的本质,这为殖民遗产旅游的展示与管理带来新的启示。     

1480-1940年广东地区气候干湿变化与旱涝灾害区域分异特征

1 IntroductionThe natural disasters, especially the flood and drought disasters, have occurred frequently inG uangdong area since ancienttim es.A ccording to historic statisticaldata,since the 17th century,the occurrence of the flood and drought disasters…