Photo-induced formation of dissolved gaseous mercury in coastal and offshore seawater of the Mediterranean basin

The first measurements on the daily trend of dissolved gaseous mercury (DGM) concentration determined in coastal and offshore waters of the Mediterranean basin are reported. Marked daily behaviour tracking solar radiation has been observed at the coastal sampling station with DGM values ranging from 11.0 to 38.9 pg/l. Contrary to these observations the DGM values in offshore water samples (11.9-20.0 pg/l) were independent of the sampling time, thus identifying the absence of higher levels during the hours of maximum insolation. The availability of Hg2+ substrate necessary for the photo-reaction processes of DGM formation has been evaluated by measuring the reactive mercury concentration. In offshore waters the lower DGM concentrations are attributable to the substrate as a limiting factor. The highest concentration of DOC measured in coastal seawater with respect to the offshore one could moreover enhance the reaction rates of DGM production through the formation of inorganic mercury complexes and weaker organic associations.     

Application of ecological models to landscape planning: the case of the Mediterranean basin

Landscapes in the Mediterranean basin have been modified by human exploitation for ages. Currently, European Community (EC) agricultural policies are reshaping land use patterns and vegetation disturbance regimes. It is uncertain how vegetation and animal population dynamics will be modified by the novel spatial patterns of habitat fragmentation and disturbance. Therefore, landscape planners need diagnostic tools to evaluate the impact of alternative management schemes on habitats and wildlife. In this contribution, we discuss the possible role of ecological models in describing how animal and plant community dynamics are affected by anthropogenic processes. First, we review models of landscape change and their applicability to habitat modeling in the Mediterranean basin. Second, we discuss different approaches to investigate the effect of habitat spatial structure on the long-term persistence of animal populations.     

Dissolved gaseous mercury production in the dark: Evidence for the fundamental role of bacteria in different types of Mediterranean water bodies

It is well established that the dissolved gaseous mercury (DGM) production in waters is mainly driven by photochemical processes. The present paper provides evidence for a significant bacteria-mediated DGM production, occurring also under dark conditions in environmentally different types of coastal water bodies of the Mediterranean basin. The DGM production was laboratory determined in sea, lagoon-brackish and lake water samples, comparing the efficiency of the DGM production processes in darkness and in the light. This latter condition was established by exposing samples at solar radiation intensity in the Photosyntetical Active Radiation region (PAR) of 200 W m^− 2. Mercury reduction rate in the dark was of the order of 2-4% of the DGM production in lightness, depending on the total mercury concentration in the water, rather than the bacterial abundance in it. Support for the active bacterial role in mercury reduction rate under dark conditions was provided by: 1) absence of significant DGM production in sterilized water samples (following filtration treatment or autoclaving), 2) restored DGM production efficiency, following re-inoculation into the same water samples of representatives of their bacterial community, previously isolated and separately cultured. Notwithstanding the low bacteria-mediated vs. the high photo-induced DGM production, whatever natural water body was considered, it is worth stressing the significant contribution of this organismal-mediated process to oceanic mercury evasion, since it occurs continuously along the entire water column throughout the 24 h of the day.     

井点降水方案的实例分析与比较

针对基坑工程复杂多变的地质条件提出联合和合理应用各种降水方法的思路,并且运用实际工程案例来进行应用效果和经济性的比较,深入剖析了联合和合理应用各种降水方法带来的好处。     

Long‐term phosphorus accumulation and removal efficiency in a land‐based wastewater treatment system in the UK

The study aims to assess the long‐term phosphorus (P) removal in a land treatment system (LTS) in the UK. Different sections of the site have been irrigated with wastewater effluent for different periods of time for up to 85 years. The amounts of P discharged and accumulated were calculated from historical data, estimations of water consumption, composition and soil measurement. The total P input during the study period was estimated to be 90 010 kg, the average P removal was 4% and there was no significant difference in the total P accumulated between plots irrigated for different periods, indicating that the sorption capacity of the soil might be saturated. Despite the low P retention rates in the LTS, there is no evidence that emissions from this system are affecting P concentrations in either the nearby river or the local chalk aquifer. Gaps remain, however, in performance optimisation and longevity forecasting.     

Empirical evaluation of river basin sustainability affected by inter‐basin water transfer using composite indicators

In this study, a practical approach to evaluate the sustainability of river basins subjected to an inter‐basin water transfer project is developed. Selection of appropriate evaluation indicators is pivotal to such approach. To make use of huge amount of data, composite indicators of sustainability (CIS) should be utilised. The proposed approach relies on 15 sustainability indicators (SI) that cover three major criteria namely (economic, social and environmental), and aggregates them into eight different types of sustainability indices for a more robust outcome. Two scenarios were considered within the source and recipient basins. Furthermore, multivariate principal component analysis (PCA) was applied to determine principal and non‐principal indicators for the two river basins. The ability of CIS and PCA methods were verified via correlation and simple regression methods respectively. The results demonstrated that inter‐basin water transfer may improve sustainability, provided that a proper water resource management is enforced.     

Watershed erosion risk assessment and management utilizing revised universal soil loss equation‐geographic information systems in the Mediterranean environments

The generation of an easily adaptable method for erosion risk assessment is important for management and conservation of the available resources in developing countries. The study aims to assess the risk of soil erosion by using an integrated, easy to apply, time‐ and money‐conserving revised universal soil loss equation‐geographic information systems (RUSLE‐GIS)‐based model in the Eastern part of the Mediterranean. Although the model showed a good efficiency in predicting the annual soil loss (R²=0.68), the limited runoff–erosion data warrant the need for long‐term data to test and calibrate the model. The model showed that 24% of the watershed area has an annual soil loss exceeding the soil loss tolerance (SLT) of the area (5 Mg/ha). When all the RUSLE factors were kept constant, except the C factor, the model showed the highest soil loss potential under olive groves (20–30 Mg/ha), and the lowest under wheat and barley (5 Mg/ha). The application of proper conservation practices to these areas is thus important, i.e. reducing the number of tillage and/or time of tillage practices.     

中欧近期生态城市建设的探讨

回顾了欧洲最近几年生态城市建设的理论和实践,分析了我国当前生态城市建设的特点,剖析了生态城市的内涵。并根据我国国情,对比借鉴欧洲的成功经验,提出了我国生态城市建设的努力方向。     

Trends and multi-decadal variability of annual maximum precipitation for Seoul,South Korea

Flood risk management is an important and difficult problem for the densely populated and rapidly urbanised city of Seoul, South Korea. This study characterises long-term trends and variability in the city's annual maximum daily precipitation (AMP) over multiple decades. Smoothing the time series reveals that recent decades have witnessed a steep upward trend in AMP. Continuous wavelet analysis shows that the AMP series has statistically significant power in the 32–60-year periodicity band between 1880 and 1960 (one full cycle is clearly visible in the smoothed series). This feature has an even wider scope in the annual total precipitation series, suggesting that a real oscillation exists. Four climate indices were investigated as possible explanatory variables for the AMP series using cross-wavelet analysis, but no significant coherence between the signals was found. Finally, mean AMP forecasts based on three interpretations of the past linear trend are provided for flood risk management.     

火灾的发展趋势和防治对策分析

从国家所处的经济和社会时期分析火灾的发展趋势,联系经济发达国家不同时期的火灾宏观现象,说明了当前我国经济上升期火灾步入“高发期”并将持续一段时间的必然性,并借鉴国外同时期的经验和教训提出了当前和以后一段时间火灾防治的对策和建议。     

中国公铁两用桥主桥结构体系分析与展望

中国公铁两用桥发展至今已有近80年的历史,从早期跨径小、结构受力简单的梁式体系发展到目前大跨径的拱式体系以及大跨径、超大跨径的斜拉、悬索体系等。通过收集中国已建和在建的以上4种结构体系的公铁两用桥相关资料,对中国4种结构体系的公铁两用桥主桥主梁结构、基础以及其他结构部分在结构设计、施工工艺、材料性能上的发展趋势进行了分析。分析发现:4种结构体系公铁两用桥主桥主梁结构设计中的主桁形式、桥面系、联结系在结构上由繁至简、由离散拼装至整体栓焊;主桁桁式在力学特性上与各结构体系公铁两用桥主梁受力特点相辅相成,充分发挥了材料的性能和结构的受力特点,主梁施工工艺趋于系统化、高效化、经济化,其材料性能趋于优质化;基础的类型没有明显变化,但其施工方法实现了自我创新,材料性能趋于优质化;拱式体系公铁两用桥主桥主拱的结构设计趋于新型化,施工工艺趋于复杂化,在材料的选择上趋于科学和经济化;斜拉和悬索体系公铁两用桥除主梁和基础部分外,其他部分结构的设计趋于科学化,施工趋于经济化、智能化,材料性能趋于优质化。     

深基坑工程降水实例分析

介绍了上海市某地铁车站深基坑工程的降水设计和现场监测实例,根据场地的工程地质和水文地质条件,对抽水试验结果进行拟合和参数反演,优化设计方案,做出降水预测,并与监测结果进行对比分析,得出一些有价值的结论。     

基坑降水工程设计中几个问题分析

从基坑降水设计参数的精度分析,方法的选定等几个问题入手进行分析,并给合工程实践提出作者的观点。     

皎口水库地震特征及震情趋势分析

探讨了坝址区地震地质构造背景，比较了皎口水库发生的地震特征，从区域构造、地震地质条件、水库规模等方面分析了未来震情发展趋势，对皎口水库的地震研獍具有一定的参考意义。     

欧洲生态街区的建设类型与经验借鉴

引介1990年代以来欧洲生态街区建设的最新实践成果,通过对若干具体案例的深入分析,归纳欧洲生态街区规划建设的3种类型,并针对各类型的特征从物质空间系统、社会文化系统和技术支撑系统等领域总结欧洲生态街区规划建设的经验及发展趋势。在此基础上,结合国内生态街区建设的问题与不足,提出通过建立政府行为、工程技术、社会运动三位一体的实践框架来推动我国生态街区的发展。     

Landscape change and the urbanization process in Europe

Urbanization is one of the fundamental characteristics of the European civilization. It gradually spread from Southeast Europe around 700 . ., across the whole continent. Cities and the urban networks they formed were always an important factor in the development and shaping of their surrounding regions. Polarization of territory between urban and rural and accessibility are still important aspects in landscape dynamics. Urbanization and its associated transportation infrastructure define the relationship between city and countryside. Urbanization, expressed as the proportion of people living in urban places shows a recent but explosive growth reaching values around 80% in most European countries. Simultaneously the countryside becomes abandoned. Thinking, valuing and planning the countryside is done mainly by urbanites and future rural development is mainly focused upon the urban needs. Thinking of urban places with their associated rural hinterland and spheres of influence has become complex. Clusters of urban places, their situation in a globalizing world and changing accessibility for fast transportation modes are some new factors that affect the change of traditional European cultural landscapes. Urbanization processes show cycles of evolution that spread in different ways through space. Urbanization phases developed at different speeds and time between Northern and Southern Europe. Main cities are affected first, but gradually urbanization processes affect smaller settlements and even remote rural villages. Functional urban regions (FURs) are a new concept, which is also significant for landscape ecologists. Local landscape change can only be comprehended when situated in its general geographical context and with all its related dynamics. Patterns of change are different for the countryside near major cities, for metropolitan villages and for remote rural villages. Planning and designing landscapes for the future requires that this is understood. Urbanized landscapes are highly dynamic, complex and multifunctional. Therefore, detailed inventories of landscape conditions and monitoring of change are urgently needed in order to obtain reliable data for good decision-making.     

基于河南百泉泉域降水量的小波分析

文章利用1951—2016年百泉泉域降水量进行小波分析,揭示了百泉泉域不同时间尺度的降水特征,对百泉泉水流量的动态分析和百泉泉域裂隙岩溶地下水资源评价具有重要意义,也可为类似地区降水分析和资源评价提供参考。小波分析结果显示:(1)百泉泉域年降水量Z值为-2.49,总体呈下降的趋势,且趋势显著。春季降水量Z值为-0.01,降水量几乎无明显变化;夏季降水量Z值为-2.67,降水量明显减少,且趋势显著;秋、冬两季降水量Z值分别为-0.98和-0.95,降水量呈减少趋势,下降不显著。(2)年降水量和四季降水量存在多个主要周期变换。在大时间尺度内,年降水量和四季降水量震荡较强;而在小时间尺度内,秋、冬两季降水量震荡较强,突变点增多。(3)2016年百泉泉域为丰水期,但未来将步入枯水期。     

羌塘盆地内部结构与反射地震勘探技术分析

位于青藏高原腹地的羌塘盆地海相地层保存较为完整,是中国最大的中生代海相含油气盆地。羌塘盆地的油气地震勘探经历了近30年的历程,在仪器设备、采集技术、数据处理和解释等方面均取得了长足进步,对羌塘盆地油气资源战略调查起到了关键作用。本文总结了羌塘盆地反射地震勘探的历程和数据采集参数,根据笔者团队多年积累的资料,揭示出羌塘盆地基底及上覆地层的结构,分析了有利圈闭构造及其对油气的影响,并根据实际情况,进一步分析了影响羌塘盆地油气地震勘探数据质量的主要因素。建议从改善激发、接收条件,优化观测系统,开展针对性处理等多个方面综合考虑,提高反射地震资料品质,获得高质量的地震剖面。     

国内外铜矿资源供需现状及趋势分析

文章以中国自然资源部、USGS和ICGS发布的年度数据为主要数据源,分析了2012-2017年国内外铜矿资源的分布、保障程度、供需的变化情况,并对发展趋势进行了预测。同时,针对我国铜矿资源保障程度低的问题提出了建议。