洮儿河流域农业生态地质环境研究

系统分析了吉林西部洮儿河流域的农业生态地质环境特征,揭示了流域内影响农业可持续发展的五大农业生态地质环境问题;按照地质、地貌、自然资源状况、生态环境灾害、环境质量等综合要素对流域进行了环境分区;最后论述了流域内农业生态地质环境的演化过程和影响因素。     

Hammarby Sjstad:斯德哥尔摩推进可持续发展方法的典范

斯德哥尔摩因其处理环境问题的方法而闻名.市政厅以获1997年度欧洲可持续城市而自豪. Hammarby Sjstad是斯德哥尔摩推进可持续发展方法的一个实例，据说这是当今北欧最大 的不断发展的建筑工程.Hammarby Sjstad的环境计划，是1996年为争当斯德哥尔摩地区生态和环境生活区的先 锋而提出的.该社区将容纳15000左右公寓居住者和300家企业.工程施工为1998－2005年.住 宅区分为几个街区，各街区都有公寓、商店、办公室和小企业.该工程按严格的生命周期分析(LCA)和生态效率原则规划和建设.所采用的解决方案对环境 造成的影响，将是当今建筑项目…     

应用随机性混合数据评价技术评价海口市污水处理厂规划方案

海南省为我国第一个特区省,海口市作为海南省的省会将建成为百万人口左右的国际现代化大城市,因而,海口市的环境规划和污水处理厂的选址规划对创造良好的现代化的城市环境起着重要的作用。本研究着重于海口市污水处理厂规划方案的评价和选择。由于污水处理厂的选址规划不仅牵涉到     

上海市污水外排工程规划与方案思考

进行了上海市污水处置现状分析，明确了污水外排选址的重要意义，为实现城市的可持续发展，结合上海市实际外环境，提出了进行邻近海域环境容量研究及污水外排选址方案的建议。     

239Pu在西南某地板岩与土壤中的吸附行为

以西南某极低放废物处置库预选场址地质环境中板岩与土壤为吸附介质,通过吸附实验和解吸实验,研究了不同介质粒径、环境温度(10℃—50℃)、水相pH(4—12)对239Pu核素在板岩与土壤介质中吸附行为的影响特征.吸附实验表明,水相环境中板岩和土壤介质对239Pu核素的吸附过程在10 d左右达到平衡,并且其吸附分配比随着介质粒径的减小而增大,随着水相pH值的增大而增大,但温度对其吸附的影响不明显.解吸实验表明板岩和土壤介质对239Pu核素的吸附是可逆的.     

有机污染物生物有效性的评价方法

环境中有机污染物的生物有效性评价对生物修复、生态毒性和环境风险研究有着重要的意义.本文概括了影响有机污染物生物有效性的因素,综述了近年来有机污染物生物有效性评价方法的发展与应用,并对该领域的研究趋势进行了展望.     

有机质官能团及微孔特性对疏水性有机污染物吸附的影响机制

作为重要的地质吸附剂,土壤/沉积物中的有机质是环境中疏水性有机污染物主要的汇.由于有机质的结构异质性,疏水性有机污染物一旦进入其中,会被吸附在不同的位点上,反应活性和生态风险进而会发生变化.对疏水性有机污染物在有机质上的吸附进行研究有助于了解其在环境中的分布,传输及生物有效性.本文就疏水性有机污染物在土壤/沉积物中的有机质上吸附的国内外研究进展进行了综述,讨论了重要有机质组分(腐殖质和碳黑)的结构和吸附作用差异性,重点分析了有机质的微孔特性和官能团对吸附的影响机制.     

人参生长光环境研究进展

光因子是直接影响植物光合作用的主导因子。人参(PanaxginsengC.A.Mey.)作为典型的阴性植物,对光环境的要求十分严格。文章从保护野山参物种资源及光环境对人参生长发育的重要作用的角度,介绍了人参生长光环境的研究现状:研究时期集中于20世纪80、90年代,以指导园参栽培为目的,围绕可见光区的光强和光质特征展开,以光环境静态调查及光强日动态、光质颜色对人参生理影响为主要研究内容。文中分析了国内外对于人参适宜光照的研究结果存在较大差异的原因可能是人参种质、不同生长阶段的光合能力及光分布空间变化给人参光合作用造成的影响。总结了已有研究的结果,例如,①参棚透光率为25%时,光照强度达到饱和光强度,人参光合速率最高;②浅绿膜人参生育健壮,光合作用强度高,干物质积累快,有利于参根增重。2000年以后,随着林下栽参的兴起,原有研究成果不足以满足目前科学种植的需要,国外已经出现林下分光谱辐射对人参根部皂甙积累影响数量关系的研究,而国内针对林下参生长光环境的研究仍停留在上世纪90年代针对可见光区光强变化的水平上。文章最后指出,现有研究成果在科学指导林下栽参的选址及现代化管理方面存在不足,通过学科交叉与融合、建立合理的人参生长光环境动态模型是未来人参生长光环境研究的发展趋势。     

密切值法在污水土地处理工程选址中的应用

本文对密切值法在污水土地处理工程选址中的应用进行了探讨，通过实例分分析看出该方法科学可行且简易。     

高等院校《环境与可持续发展》课程建设的思考——以北京石油化工学院为例

《环境与可持续发展》是国内各高校开设的一门公共选修课程。为了更好地发挥该课程在高校环境教育中的重要作用,本文以北京石油化工学院开设的《环境与可持续发展》课程为例,就该课程在课程建设中所取得的成绩和存在不足进行总结,并对该课程的后期建设提出了一些新的思考。     

Estimation of the density of a clustered point pattern using a distance method

Distance-based methods use point-to-point distances or random-location-to-point distances in a cloud of points to estimate characteristics of the point pattern. One such characteristics is the density of points. The difficulty with distance-based density estimators is that their distribution depends on the spatial pattern of points. In particular, the distribution of distances is untractable for usual clustered patterns, that are often observed in natural systems. Here, we propose a density estimator for clustered patterns, based on the random-location-to-pth-point distance X _p . An approximate expression for the distribution function, F _p , of X _p was obtained by identifying the first two moments of the count of individuals in disks for a given point process with the first two moments of a negative binomial distribution. The approximate expression of F _p was then used to derive a maximum-likelihood estimator of the intensity of the point process. The quality of the approximation of F _p was assessed for homogeneous Poisson processes (for which the expression of F _p is exact) and for Matérn processes. The intensity estimator based on Matérn processes was then used to estimate tree density in a tree savanna in Mali, and it compared favorably with six robust estimators found in the literature.     

Estimating the objectives of a public firm in a natural resource industry

The purpose of this paper is to understand the behavior of policymakers in a public firm. To accomplish this goal, the objectives of a government-owned firm operating in the Saskatchewan uranium industry are econometrically estimated. The estimates are used to determine the importance policymakers attach to the outcomes resulting from their behavior and to examine how the firm might respond to changes in its economic environment. Empirical results indicate that the public firm is willing to reduce profits in order to increase employment and reserves.     

Change in a bacterial population during the process of degradation of a phytoplankton bloom in a brackish lake

Change in a bacterial population during the process of degradation of a phytoplankton bloom was investigated at Lake Hamana, Japan in June 1981. The predominant phytoplankton were Prorocentrum micans Ehrenberg and P. triestinum Schiller. While most phytoplankton cells were living and moving actively, most bacteria were those in a free-living state (free-living bacteria) and the number of bacteria associated with particulate materials (attached bacteria) was less than a few percent of the total bacterial number. As the decline process proceeded, the number of free-living bacteria remained almost constant or decreased slightly; on the other hand, the number of attached bacteria increased gradually and reached about 40% of the total bacterial number. These results indicate that some of the free-living bacteria become attached to particulate organic matter and grow on the surface of the particles.     

Starvation-induced barotolerance as a survival mechanism of a psychrophilic marine vibrio in the waters of the Antarctic convergence

Ant-300, a psychrophilic marine vibrio isolated from the Antarctic convergence, was tested for survival under conditions simulating those expected in situ for this organism. In particular, the organism's response to increased hydrostatic pressure was examined. Under a hydrostatic pressure of 250 atm, the viability of Ant-300 was reduced over 755 in growth media and under starvation conditions after 3 and 2 days, respectively. However, if the cells were starved for 1 week prior to pressurization of the starving suspension, 100% viability was maintained for over 6 weeks at the same pressure. After 10 weeks, the viability of a population of cells suspended for 1 week in natural or artificial seawater at a density of 10³ cells ml^–1 prior to pressurization of the suspension was 2 to 3 times greater than 1 atm controls. The data indicate that starvation conditions are a contributory if not the primary factor for the barotolerance of this organism in Antarctic waters. The data also indicate that under certain conditions, not unlike those expected in situ, hydrostatic pressure actually increases the survival of this organism under low nutrient conditions.Technical Paper No. 4907, Oregon Agricultural Experiment Station.     

Experimental test of the effects of a non-native invasive species on a wintering shorebird

The abundance of nearly one-quarter of the world's shorebird species is declining. At the same time, the number of non-native species in coastal ecosystems is increasing rapidly. In some cases, non-native species may affect negatively the abundance and diversity of shorebird prey species. We conducted an experimental study of the effects of the introduced European green crab (Carcinus maenas) on prey consumption by wintering Dunlin (Calidris alpina) in a central California estuary. We placed green crabs and Dunlin sequentially in field enclosures and measured changes in density of benthic invertebrate prey (e.g. polychaetes and small clams), Dunlin biomass, and gut contents of both Dunlin and crabs and observed foraging behavior of Dunlin. Green crabs significantly affected Dunlin foraging success through both direct and indirect multitrophic linkages. In enclosures with high densities of green crabs, crab foraging reduced the availability of polychaetes, and Dunlin consumed significantly fewer polychaetes compared with Dunlin in enclosures without crabs. High densities of green crabs were also associated with increased availability of small clams. Dunlin consumed significantly more small clams compared with Dunlin in enclosures without crabs. In our literature survey of studies of effects of non-native invasive species on shorebirds, we found three prior experiments that addressed the effect of non-native invasive species on shorebirds. Results of two of these studies showed positive direct effects of non-native invertebrates on shorebirds, 1 showed negative direct effects of a non-native plant on shorebirds through habitat conversion, and none showed indirect effects of non-native invertebrates. We suggest future management of shorebirds explicitly examine how non-native marine species, particularly invertebrates, directly and indirectly affect shorebirds.     

Preliminary Evidence of a Barrier Effect of a Railroad on the Migration of Mongolian Gazelles

Abstract:  Much remains to be learned about how anthropogenic structures affect migration in large mammals. We examined the potential influence of the international railroad in Mongolia on migration in Mongolian gazelles (Procapra gutturosa). We examined gazelle movements and the normalized difference vegetation index (NDVI) on both sides of the railroad. The tracked gazelles never crossed the railroad, despite movements that mainly followed the railroad in winter and higher NDVI values on the opposite side. It is likely that the railroad had a barrier effect on gazelle migration because it split the gazelles' habitat. Our results, although based on an extremely small sample, have utility in indicating approaches that might be useful for examining migration in ungulates.     

Comparison of the sedimentation of a diatom spring bloom and of a subsurface chlorophyll maximum

The seasonal pattern of sedimentation was determined over a 8-mo investigation period covering the productive season at a permanent station in the Southern Kattegat (Denmark) in 1990. The phytoplankton succession was characterised by a 4-mo long subsurface maximum associated with the pycnocline which was entirely dominated by the dinoflagellate Gyrodinium aureolum. The bulk sedimentation of organic matter took place during this period and accounted for >60% of the annual particulate organic carbon (POC) and particulate organic nitrogen (PON) sedimentation. The spring bloom period contributed 60% of the sedimentation of intact phytoplankton cells, but only 20% of the POC and PON sedimentation. A minor fraction of the sedimenting matter from the subsurface phytoplankton maximum consisted of intact phytoplankton (<20%), suggesting that the phytoplankton was processed by heterotrophs and that it was mainly products from this activity which contributed to thevertical flux of organic matter. The variation in oxygen concentration below the pycnocline coincided with the pattern of sedimentation with a delay of 3 to 6 wk.     

Identification and Choice of a Biological Indicator for the Study of the Contamination of a River Environment by Heavy Metals

Biological indicators are efficient tools for establishing pollution levels in a given environment (Phillips, 1980). In this study the organisms used are endowed with the ability to accumulate heavy metals in the river ecosystem, where a biological indicator may be preferable to direct analysis of water samples as a means of monitoring pollution (Popham and D'Auria, 1981). Further, biological indicators provide estimates of the average level of pollution over a given period of time, and can discriminate a given pollutant present in water on the basis of its biological availability. The selection of a suitable organism, however, should fulfil other requirements, thus it must be sedentary, abundant in various environments and longeval. In the Po river a bivalve mollusc (Unio elongatulus) and some macrophytes (Potamogeton crispus, Lagarosiphon major, Miriophyllum verticillatum, Phragmitescornrnunis), known for their bio-accumulative properties (Ravera, 1966, 1973) have been identified as possible biological indicators of heavy metals (Pb, Cd, Cu, Zn, Ni, Co, Cr, Mn, Fe).