华南南亚热带不同演替阶段植被的环境效应

This study deals with the capacity for nutrient conservation,the balance of carbon and oxygen as well as the buffering of acid rain in the succession of vegetation of lower subtropical zone of southern China.The results show that:(1)N,P,K contents of plants of a 100 year old monsoon evergreen broad leaved forest were 12～39 times those of the grassland and fernland.They were 12～16 times those of the shrubland.Its N,P,K contents of litter were 11～36 times those of grassland and fernland,and 3.1～5.2 times tha...研究华南南亚热带不同演替阶段植被对养分保护、碳氧平衡和对酸雨的缓冲作用的结果表明: 100 年生季风常绿阔叶林植物N、P、K 贮量是草地和芒萁群落的12 ～39 倍, 灌木林的12～16 倍; 死地被物N、P、K 贮量是草地和芒萁群落的11～36倍, 灌木林的3. 1～5. 2 倍. 30 年生季风常绿阔叶林净初级生产量的N、P、K 贮量是草地、芒萁、灌木群落的1. 9～5. 1 倍. º 100年生季风常绿阔叶林植物碳贮量是草地、芒萁、灌木群落的13～49 倍. 30 年生季风常绿阔叶林植物碳净固定量是草地、芒萁、灌木群落的2. 3～3. 4 倍, 前者的氧释放量也明显大于后者. » 芒萁、灌木群落和季风常绿阔叶林穿透雨的平均pH 值比降雨pH 值分别高1. 13、1. 03 和1. 90 个单位, 季风常绿阔叶林对酸雨的缓冲能力明显高于芒萁、灌木群落. ¼正向演替可加强植被的环境效应, 让草地、芒萁、灌木群落演替成为季风常绿阔叶林, 有利于区域生态环境的改善.This study deals with the capacity for nutrient conservation, the balance of carbon and oxygen as well as the buffering of acid rain in the succession of vegetation of lower subtropical zone of southern China. The results show that: (1)N,P,K contents of plants of a 100 year old monsoon evergreen broad-leaved forest were 12-39 times those of the grassland and fernland. They were 12-16 times those of the shrubland. Its N,P,K contents of litter were 11-36 times those of grassland and fernland,and 3.1-5. 2 times that of the shrubland. The mass of N,P,K in net primary production of 30 year old monsoon evergreen broad-leaved forest were 1. 9-5.1 times those measured in the grassland,fernland and shrubland. (2)Carbon content of plants of the 100 year old monsoon evergreen broad-leaved forest was 13-49 times those of in the grassland,fernland and shrubland. The amount of fixed carbon in the 30 year old monsoon evergreen broad-leaved forest was 2. 3-3. 4 times those of the grassland,fernland and shrubland. The amount of oxygen made in the former was,obviously,also greater than in the latter. (3)Mean pH values of throughfall from the fernland, shrubland and monsoon evergreen broad-leaved forest were 1. 13,1. 03 and 1. 90 units higher than that of rainfall. The buffering capacity of the monsoon evergreen broad-leaved forest for acid rain was significantly higher than that of the fernland and shrubland. (4) The environment effects of vegetation could be increased by succession. It is very helpful for improving the eco- environment if the grassland,fernland and shrubland are changed to monsoon evergreen broad-leaved forest by succession.link_to_subscribed_fulltextpostprin

Trial airborne environmental and geological survey: an initial appraisal of relevance to land-use

A series of four trial airborne environmental and geological surveys was flown by the Geological Survey of Finland (GTK) in collaboration with the British Geological Survey (BGS) in June 1999; the trials were co-sponsored by the Department of the Environment, Transport and the Regions and the Environment Agency. The main objective of these surveys was to test the efficiency of the GTK airborne electromagnetic system in the mapping of potential pollution problems in the UK environment. Gamma spectrometric and magnetometric measurements were also collected to see to what extent these techniques provide complementary information. This report is an initial consideration of the multi-parameter airborne geophysical data in relation to land-use issues. A variety of earth science information for planning and development already exists. The baseline information is reviewed according to scale and resolution. It is noted that the airborne data is of a new type with regard to both information content and spatial continuity. The specific characteristics and advantages of the airborne geophysical data are emphasised. The trial survey data were obtained at high resolution and a large number of anomalous responses have been observed. Since the information is provided at a local-scale a number of issues concerning the nature of the responses observed and the underlying causes have been raised. It will be necessary to improve our understanding of the data before an unambiguous discussion of their specific relevance to land-use issues can proceed. In advance of detailed interpretations of the trial data, the data are presented and discussed in relation to their potential relevance to five land-use issues: (i) Waste planning/Planning and pollution control, (ii) Minerals Planning, (iii) Water supply and water resource protection/Coastal zone management, (iv) Urban regeneration/Peripheral development and new communities and (v) Agriculture and Forestry. It is acknowledged that there are differences between the information needed for planning the use of land, and information which is required for monitoring environmental strategies. The geophysical data appear to have greatest relevance to the latter requirement. Recommendations for ground and subsurface calibration of the data are made

Hydrogeological classification of superficial clays: apparent resistivity measurements from the Garboldisham, Norfolk pilot study area

Three types of apparent resistivity measurements have been undertaken at the Garboldisham pilot study area in Norfolk in support of the superficial clays programme. Resistivity soundings have established the intrinsic resistivities for the strata encountered. Cover sand (possibly mixed with glacial sand) ofresistivities 100 - 200 ohm.m overlies till ofresistivities 22 - 32 ohm.m which lies directly on chalk of resistivities 65 - 85 ohm.m. At the sounding sites, depth to chalk is in the range 11 - 15 m. Azimuthal apparent resistivity measurements were made in an attempt to identify fracture sets within the till and to establish the degree of fracturing between measurement sites. These fracture sets will have an important influence on the hydrogeological regime. At only two of the five sites investigated was a fracture trend recognised and this had an orientation of 210-225 degrees. There was an indication of a change in the intensity of fracturing between the two sites. The results indicate that there is either a lack of fracturing with a consistent trend within the till or that there is an insufficient resistivity contrast between the conductive till and the fractures. Detailed dipole-dipole apparent resistivity measurements undertaken with the BGS RESCAN system were able to map the thickness ofcover sand over a suspected sand channel. The sand body has a north - south orientation with a variable depth to the till surface. Maximum depths are up to two metres. The effectiveness of the resistivity technique for mapping sand lying on till has been demonstrated in this study

Requirements of a global information system for corn production and distribution

There are no author-identified significant results in this report

The High Resolution Airborne Resource and Environmental Survey- (Phase 1) (HiRES-1): background, data processing and dissemination and future prospects

This report provides an overview of the HiRES-1 airborne geophysical survey of Central England. The BGS and World Geoscience (UK) Ltd. carried out the survey jointly in 1998. The three main survey data sets acquired were magnetic, radiometric (gamma ray spectrometry) and Very Low Frequency (VLF) electromagnetic. The main aim of the report is to provide information on the acquisition, processing and storage of the final data and map products produced by the HiRES-1 project. Additional descriptions of ground truthing activities, data licensing and dissemination are also provided. A significant aspect of the project was the assessment of the potential of, and issues raised by, modern, multi-parameter, regional-scale airborne geophysical surveys in the UK context. Some of the main issues outlined in the report are: • The practical difficulties of conducting extensive low level, fixed-wing geophysical surveying in the UK. Issues discussed include CAA regulatory permissions, flight height adjustments above conurbations and surveying near areas with dense air traffic. • The processing challenges introduced by cultural (nongeological) influences on high resolution airborne magnetic data sets in the UK. • The significant amounts of detailed geological and environmental information contained within the radiometric data. • The weak application potential provided by passive (i.e. VLF) measurements, in contrast to active airborne electromagnetic techniques. The future prospects for regional-scale, airborne geophysical surveys in the UK are considered. Such prospects are also influenced by a further set of trial airborne data, obtained in 1999, but not described here. Further detail of the HiRES-1 survey, productivity, technical specifications and data pre-processing are contained in the survey logistics report prepared by WGL: ‘British Geological Survey “Hi-Res Phase One” Airborne Geophysical Survey (Survey Details, Technical Specifications & Processing Summary)’ (WGL 2000)

Trial airborne environmental and geological survey of target areas in the English Midlands

A series of four trial airborne environmental and geological surveys was flown by the Geological Survey of Finland (GTK) in collaboration with the British Geological Survey (BGS) in June 1999; the trials were co-sponsored by the Department of the Environment, Transport and the Regions and the Environment Agency. The main objective of these surveys was to test the efficiency of the GTK airborne electromagnetic (EM) system in the mapping of potential pollution problems in the UK environment. Gamma spectrometric and magnetometric measurements were also collected to see to what extent these techniques provide complementary information. The EM data are particularly encouraging and have identified anomalies which may relate to subsurface pollution. The data have identified conductive zones both on the ‘local’ scale (i.e. possibly emanating from domestic landfills) through to regional scale features up to many kilometres in length. The information obtained in relation to spoil tip drainage is of particular note. The data have provided a wealth of information on ‘point source’ anomalies (requiring ground truth information) and diffuse sources that may be connected with groundwater extraction. At two sites (Trent Valley and Langar) the EM technique appears to have met the challenge of detecting conductive targets in a conductive host. Many other features of the data will take time to assess. The radiometric data indicate features of land fill and colliery spoil sites and allow comparison to be made rapidly with the EM data to define the lateral spread of conductive pore fluids beyond the site itself. They can also be used to map site-specific contamination where radioactive elements are present. The radiometric data also give direct indications of solid and drift geology and soil type, providing additional detail to that shown on geological maps (soil maps are not available for much of the UK). The magnetic data have suggested the presence of significant volumes of metallic debris in the Langar landfill sites. This may be significant in terms of the leachates derived and the compaction (through time) of the contrasting fill materials. Compared with the EM and radiometric techniques, the applications of magnetics in environmental studies are rather limited, but such data is worthwhile collecting in view of the marginal additional costs involved

Applications and challenges for high resolution airborne surveys in populated areas

The role of high resolution airborne surveys is extending well beyond the traditional areas of mineral and hydrocarbons exploration and regional mapping, which were often focused on the relatively unpopulated and remote regions of the world. As an increasing proportion of the Earth’s surface is affected by human activity, airborne survey techniques are being adapted and applied to development-related issues in more populated areas. The value of radiometric and electromagnetic data (in particular) has been recognised for addressing a range of environmental issues and, more generally, airborne surveys are seen as an effective, non-invasive means of providing multiple development-related geoscience data sets in a single operation. These new applications present many operational, processing and interpretation challenges. This paper provides an overview of some of the issues addressed in this Special Session on ‘The role of high resolution airborne surveys in environmental monitoring and sustainable development of resources’

Adolescents' experiences of street harassment: creating a typology and assessing the emotional impact

Purpose: Research examining young people's experiences of harassment has tended to focus on the school and digital environment. Despite street harassment being identified as a common experience for adult women, very few studies have explored adolescents' experiences of street harassment. Methodology: A person centred analytical approach, based on experienced reporting, was used to create a typology of street harassment. Reports of street harassment were received from 118 (68 female, 43 male, 7 no gender reported) 11- to 15-year-olds over a 6 to 8 week period. Findings: Cluster analysis revealed four distinct groups: "predominately verbal", "non-verbal/non-direct", "other incident", and "all forms". Young women and those in the "all forms" group reported experiencing greater negative emotions following the episode of street harassment. Young men were equally as likely as young women to report experiencing street harassment. Value: The findings uniquely highlight that adolescents experience distinct types of street harassment and some of which are associated with negative emotions

Natural water softening processes associated with waterfall effects in Karst areas

The reduction of water hardness, which occurs at waterfalls on rivers in karst areas, is considered to be a result of the waterfall effects. These consist of aeration, jet-flow and low-pressure effects. Waterfall effects bring about two physical changes in river water: an increase in the air-water interface and turbulence. A series of experiments was designed and implemented in order to investigate whether these effects and associated physical changes may cause a reduction of water hardness. From an experiment involving the enlargement of interface area, the plot of air-water interface areas against conductivity revealed that the higher the air-water interface, the more rapidly conductance declines (and Ca2+ is precipitated). A bubble producer was designed and used to simulate bubbles that are produced by aeration and low-pressure effects and a faster decline of water hardness was observed at the location with bubbles in this experiment. When a supersaturated solution was passed through a jet-stream producer, a rapid reduction of water hardness and an increase of pH appeared. Field measurements were used to support the laboratory experiments. Work on the Ya He River and at the Dishuiyan Water-falls revealed that places with aeration had the quickest hardness reduction and the highest average rate of calcite deposition.在喀斯特地区,水流过瀑布后硬度会发生降低,这种现象一般称为瀑布效应,其中包括汽化,射流和低压作用。瀑布效应会引起两种河水物理性质的变化,即气-水界面面积和涡流的增加。为了弄清瀑布效应和这些物理性质变化是否会减少水的硬度,本研究设计并进行了一系列的试验。通过改变气-水界面面积试验,发现界面面积越大,导电率降低的速率越快,由此造成Ca2+ 的沉淀。利用自行设计的气泡生成器进行试验,发现有气泡发生的地方,水的硬度降低很快。试验还发现,从射流器喷出的超饱和溶液的硬度快速减小,而pH 值增大。鸭河和滴水岩瀑布的实际观测证实,有汽化现象发生的地方,水的硬度降低很快,钙沉淀的平均速率也最高。published_or_final_versio

Methods for the recognition of geological weakness zones and other surface discontinuities caused by underground mining in Carboniferous terrain

Since March 1992 the British Geological Survey (BGS) has collaborated in a CEC part-funded project under the leadership of Dr Clasen of Saarberg, Saarbrueken, Germany. The aim of this project was to determine the most efficient combination of surface geophysical techniques to be used in combination with airborne optical scanning data for the routine detection of shallow faults. Such features, when reactivated following undermining, may become the locii of damaging subsidence, but where they can be traced in advance of mining operations then remedial measures (such as underpinning etc) may be undertaken. This final report outlines the geophysical methods applied and describes our most significant results. Conclusions are drawn concerning the relative efficiencies of each technique and possible complementary applications