乌江梯级水库水陆交错区湿地植物群落分布格局及多样性初探

水库修建对湿地植物多样性和分布格局的影响是目前研究的热点。梯级水库由于开发时间的不同而成为理想的利用空间代替时间的研究平台,即可以通过不同开发时间水库植物群落结构的横向比较,从时间尺度上评估水电开发对水陆交错区湿地植物分布格局的影响。本研究选取乌江上游代表性的8座梯级水库,在其水陆交错区通过建立3条不同样带,比较分析不同水库间以及不同样带间湿地植物多样性和分布格局,探讨水库修建对湿地植物格局的影响。调查结果表明,乌江干流8个水库湿地植物共84科199属247种,其中物种最多的科为禾本科(Gramineae),共计24种,物种最多的属为蓼属(Polygonum)共计6种,优势物种分别为白茅(Imperata cylindrica)、盐肤木(Rhus chinensis)、金樱子(Rosa laevigata)、小白酒草(Conyza canadensis)和狗牙根(Cynodon dactylon)。就湿地植物分布格局而言,乌江梯级水库植物群落呈现出明显的带状分布格局,第一条样带即水库消落区植物多样性与非消落区(第二、第三条样带)差异明显,消落区不同样点间多样性与水库海拔、水库修建时间、水库坡度密切相关,后续湿地植物的研究将重点关注梯级水库的消落区。     

苯噻草胺在不同水质中的光化学降解研究

对苯噻草胺在纯水、天然水以及不同pH值缓冲溶液中的光化学降解进行了试验.结果表明,在氙灯和高压汞灯下,各种天然水中苯噻草胺的光解半衰期顺序均是稻田水＞江水＞湖水＞河水＞重蒸水,氙灯下的半衰期为607 80～1016.40min,高压汞灯下的半衰期为12.31～18.53min.室温下强碱性溶液中（pH=11.92）的苯噻草胺易水解.高压汞灯下强酸性（pH=1.98）、强碱性（pH=11.92）溶液中苯噻草胺的光解较纯水中快,光解半衰期分别是6.04min（pH=1.98）、6.51 min（pH=11.92）和6.75 min（纯水）.光解产物的HPLC-MS检测表明,苯噻草胺的光解以醚键和酰胺键的断裂为主.     

长期土壤酸化模型(LTSAM)

以碱总量守恒为基础，以Ｕｌｒｉｃｈ缓冲范围为模型主要框架建立了兼能描述酸性与石灰性土壤长期酸化反应过程的动态模型．经与ＳＭＡＲＴ模型在理论设计和模拟结果两方面作对比之后，又利用新建模型以北京地区典型褐土为例进行了硫沉降与酸（Ｈ＋）沉降的对比计算．结果表明：（１）ＬＴＳＡＭ模型能够很好地反映土壤缓冲酸的主要机制．（２）模式运行即稳定又省时．（３）大气硫沉降不同于酸沉降．也就是说，硫沉降改变时，阳离子（尤其是主要离子）沉降量的变化应当加以考虑．     

"罐中罐"技术在炼油废水处理中的工业应用

介绍了具有复合功能的水力旋液型均质、除油、沉淀、调节罐(WS-Ⅱ型、简称“罐中罐”)技术和设备的开发和工业应用的情况,通过生产实践和现场标定,显现了该设备具有较高的除油能力和缓冲调节能力。其可靠的收油、排泥设施使得运行稳定。基本上解决了现存污水调节罐的问题。设计思想独特新颖,操作简便可靠,值得推广和应用。     

Sensitivity of soils to acid rain in South China

This paper deals with the sensitivity of soils to acid rain in 5 provinces, South China. Based on field work and literature, and taking soil pH, CEC, and the types of residua into account, the authors classified the sensitivity into 4 categories: highly sensitive, sensitive, slightly sensitive, and non-sensitive. By overlapping the maps of soil pH, CEC, and types of residua, the map of soil sensitivity in South China has finally resulted.The authors try to summarize the regularity of soil sensitivity to acid rain in this area. The sensitivity of different soil types in the studied area has also discussed.The seriousness and its prospects of acid rain in this area have been pointed out in order to draw the attention of relevant authorities.     

AQUATIC HABITAT CONDITION INDEX,STREAM TYPE,AND LWESTOCK BANK DAMAGE IN NORTHERN NEVADA1

ABSTRACT: The quality of stream habitat varies for a variety of natural and anthropogenic reasons not identified by a condition index. However, many people use condition indices to indicate management needs or even direction. To better sort natural from livestock influences, stream types and levels of ungulate bank damage were regulated to estimates of aquatic habitat condition index and stream width parameters in a large existing stream inventory data base. Pool/riffle ratio, pool structure, stream bottom materials, soil stability, and vegetation type varied significantly with stream type. Pool/riffle ratio, soil and vegetation stability varied significantly with ungulate bank damage level. Soil and vegetation stability were highly cross-correlated. Riparian area width did not vary significantly with either stream type or ungulate bank damage. Variation among stream types indicates that riparian management and monitoring should be stream type and reach specific.     

Interacting Effects of Landownership, Land Use, and Endangered Species on Conservation of Southwestern U.S. Rangelands

Abstract:  The contemporary southwestern United States is characterized by fire-adapted ecosystems; large numbers of federally listed threatened and endangered species; a patchwork of federal, state, and private landownership; and a long history of livestock grazing as the predominant land use. I compared eight sites in southern Arizona and New Mexico to assess the interacting effects of these characteristics on conservation practices and outcomes. There was widespread interest and private-sector leadership in restoring fire to southwestern rangelands, and there is a shortage of predictive scientific knowledge about the effects of fire and livestock grazing on threatened and endangered species. It was easier to restore fire to lands that were either privately owned or not grazed, in part because of obstacles created by threatened and endangered species on grazed public lands. Collaborative management facilitated conservation practices and outcomes, and periodic removal of livestock may be necessary for conservation, but permanent livestock exclusion may be counterproductive because of interactions with land-use and landownership patterns.     

DISSOLVED GAS ANALYSIS FOR ASSESSING THE FATE OF NITRATE IN WETLANDS1

ABSTRACT: Dissolved gas analysis permits direct detection of ground water denitrification, a technique we used in this study to assess the fate of nitrate in a riparian wetland. Dissolved argon (Ar) and dinitrogen (N₂) were measured in transects of nested piezometers installed at different depths within upwelling regions of a riparian wetland. The method uses the Ar content in the water as a natural inert tracer for assessing background content of N₂ from the previous air/water equilibrium. Within the wetland under study, anoxic to suboxic ground water became more oxic in piezometers close to the aquifer layer, indicating upwelling of oxic ground water. Assessment of loss of nitrate and Ar in ground water within an upwelling zone indicated that shallow piezometers had significant N₂ loss through degassing. Most of the measured nitrate‐nitrogen (NO₃^?‐N) loss of 205 μM in a piezometer nest could be accounted for by total N₂‐N produced (169 μM N), calculated from changes in dissolved N₂ and estimated N₂ degassed. Degassing due to methane (CH₄) production was also detected in some shallow piezometers within nests. This technique for analysis of dissolved gases in ground water can be applied to detect small changes in N gas concentration and aids in assessing the fate of nitrate along a ground water flow path.     

Restoration of Riparian Buffer Function in Reclaimed Surface Mine Soils

Ecosystem processes such as water infiltration and denitrification largely determine how riparian buffers function to protect surface water quality. Reclaimed mine areas offer a unique opportunity to study the restoration of riparian function without the confounding influence of past land use. Between 1980 and 2000 in southern Illinois, agricultural fields with forest buffers were established along three restored stream reaches in reclaimed mine land. Our research objective was to compare common indicators of soil quality (infiltration, soil C and N, bulk density, and soil moisture) between forest and cultivated riparian zones to determine if riparian function was being restored. Soil bulk density was significantly lower in the forest buffers compared to the agricultural fields. The forest buffers had greater soil total C, total N, and moisture levels than agricultural fields likely due to greater organic matter inputs. Soil total C and N levels in forest buffers were positively related to age of restoration, indicating soil quality is gradually being restored in the buffers. Restoration success of riparian buffers should not be estimated by the return of structure alone; it also includes reestablishment of functions such as nutrient cycling and water retention that largely determine water quality benefits. Watershed planning efforts can expect a lag time on the order of decades between riparian restoration activities and surface water quality improvement.     

河岸荆三棱带改善河水水质的中试研究

在1 a的时间里利用中试规模的荆三棱河岸带对受污染河水进行处理,主要考察了COD、NH⁺₄-N、TP、浊度和水温等水质指标.结果表明,荆三棱带在夏、秋季改善河水水质的效果好于冬、春季.荆三棱带在夏季对COD、NH⁺₄-N、TP和浊度的去除率分别为44.10%、78.66%、69.44%、99.53％,在冬季对河水水质也有一定程度的改善.荆三棱带可以降低河水温度及河水早晚温差,起到改善局部水环境的作用.荆三棱带与空白带的对比表明植物对去除水中污染物、改善局部水环境起着重要作用.