大沽河地下水库的脆弱性评价

在大沽河地区自然地理和水文地质调查的基础上,利用MapInfo建立缓冲区功能来划分评价区域,运用日前常用的DRASTIC方法进行了全面的脆弱性评价．研究结果表明：大沽河地下水库大部分地区约60．8％属于脆弱性中等的区域,25％属于脆弱性较强的区域,另外还有10．1％属于脆弱性较弱的区域,即大沽河地下水库库区是相对脆弱的,应尽量避免兴建污染性强的项日,减少化肥和农药的使用,防止地下水污染的发生和发展．     

长江口北槽悬沙输移机理分析

运用通量机制分解法对长江口北槽深水航道的实测水文泥沙资料进行了分析,将悬沙通量分解成了8个动力项,从平流输沙、潮泵效应输沙和垂向净环流输沙三方面综合分析了长江口北槽的悬沙输移特征。研究结果表明:在水文资料实测年份时,北槽输沙主要来源于上游来沙;平流输沙项占总体净输沙的比重最大;潮泵输沙所占比例较小;航道内的各测点的垂向净环流输沙主要受欧拉余流控制;深水区悬沙含量垂向变化明显,河口浅水区,表底余流方向不同,垂向净环流输沙作用增强。     

淮河上游生态需水量计算分析

为分析计算淮河上游河流生态需水量,提出了丰水期、枯水期、平水期保证率分别为45%,75%,50%的淮河上游适宜生态径流计算方法,选用淮河上游干流息县、长台关以及大坡岭3个主要控制站1960～2005年历年天然来水量资料,计算了淮河上游最小生态径流和适宜生态径流,并运用Tennant法进行评价.结果表明,最小生态径流在很大程度上有损于河流生态系统稳定与健康;总体而言,3站适宜生态径流均可以使淮河上游河流生态环境状况达到最佳,但在某些年份各站实测月均流量小于其适宜生态径流量,而且丰水期适宜生态径流破坏率较枯水期的要高.因此,在某些年份为满足淮河上游适宜生态需水要求,还应增加河道内生态用水量.     

长江口及其邻近海域近代沉积物中甲藻孢囊的垂直分布

于2005年4～5月,在长江口外及浙江中南部海域设置5个采样站点,获取了15～40 cm的沉积物柱状样,分层研究了甲藻(dinoflagellates)孢囊的垂直分布.在本研究中共鉴定出46种甲藻孢囊,其中自养型19种,异养型27种.长江口海域复杂的流系特征及环境状况对孢囊分布有明显影响,致使孢囊丰度较低,平均丰度为366.2cysts·g-1,且无明显垂直分布规律.锥状斯氏藻孢囊是最为丰富的自养型甲藻孢囊,平均质量分数介于17.0%～28.9%;异养型甲藻孢囊以原多甲藻属为主,平均质量分数为29.5%～53.6%,其它类型孢囊仅零星分布.有毒藻亚历山大藻孢囊在各站位均有分布,但丰度较低,最高值仅为68.1 cysts·g-1.     

Photosynthesis of Populus euphratica and its response to elevated CO2 concentration in an arid environment

The photosynthetic characterization of Populus euphratica and its response to the elevated carbon dioxide concentration ([CO2]) were analyzed based on its net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), and water use efficiency (WUE) at different groundwater depths measured by a portable gas exchange system (LI-6400) in the lower reaches of the Tarim River. The results showed that the elevation of [CO2] decreased the gs, and increased the Pn, Ci and WUE of P. euphratica. However, the effects of the elevated [CO2] on gs, Pn, Ci and WUE varied considerably with groundwater depth. The response of photosynthesis to rising [CO2] was stronger at the greater groundwater depth (more than 6 m) than that at the shallower groundwater depth (less than 6 m). The critical groundwater depth required to maintain the normal survival of P. euphratica was less than 6 m. When the groundwater depth increased to more than 6 m, P. euphratica encountered moderate water stress, and the plant suffered severe water stress when the groundwater depth increased to more than 7 m.     

Effects of water treatments on the activation of soil seed banks – A case study on the lower reaches of the Tarim River

Evaluation of seedling emergence is a common method used to investigate the vegetation restoration potential of soil seed banks. Previous studies have primarily been conducted in the laboratory using a single water treatment. However, when this method is used, it is difficult to optimize the water conditions for the needs of the individual species of seeds. Additionally, the germination conditions for seedlings in the laboratory are different from those in nature. To avoid these issues, we conducted experiments to activate soil seed banks in the field using different water treatments. The results revealed that: (1) generally, the number of species and quantity of seedlings decrease gradually as the water supply decreases, but that for several species most seedlings did not appear when they were provided with the greatest amount of water, and (2) different species present different germination characteristics. According to the rate of seedling emergence, the species were classified into two germination types: fast and slow. In addition, each species also had a unique climax period of emergence, which was delayed with a decrease in water supply. Therefore, the amount of water provided is vital to seedling emergence, and various water treatments should be evaluated when studying the characteristics of different species in soil seed banks. For the lower reaches of the Tarim River, the optimal soil moisture for seedling emergence ranged from 23% to 28%, and seedling conservation should be strengthened during the climax period of emergence (9–15 days from the day when water became available). These results highlight the importance of the use of an optimal water treatment and demonstrate the danger of using a single treatment method. Our results also emphasize the need for a preliminary study prior to conducting studies to evaluate seed banks.     

遗传算法在水污染控制系统规划研究中的应用

将遗传算法应用于以汾河太原城区段南内环桥至小店桥为研究对象的水污染控制系统规划研究,将遗传算法在水污染控制系统规划研究中具体化,其应用结果较为满意.结果表明该算法对目标函数的形式与性质要求较低,可在全局范围内搜索并快速收敛,实现了水污染控制系统规划模型最优求解,且编程简单,易于将计算机技术应用其中.     

引黄北干输水线路黄土湿陷性工程地质研究

黄土地基的湿陷性是引黄北干输水线路的主要工程地质问题。论述了黄土湿陷性的成因及其地基评价,并提出了处理措施。     

The shape character and development stage of nebkha

Based on statistical analysis on morphological data of nebkhas surveyed in the Hotan River Basin, Xinjiang, the changing regularity and characters of nebkhas’ morphology in different development stages have been discussed. Results indicate that there exist better correlation among length, width and altitude of all kinds of nebkhas, but there are certain various shape characters in different nebkhas and the same type of nebkhas in differential development stages. On account of analysis on mathematical imitation of nebkhas’ shape characters, regional ecological environmental and aeolian characters, the development of the nebkha can be divided into a growing stage, a stabilizing stage and a declining stage.     

基于熵权物元可拓模型的黑河流域草原生态安全评价

针对黑河流域草原生态环境的特点,基于P—S—R模型,采用物元可拓理论和熵权法构建了草原生态安全综合评判模型,对黑河流域各县区草原生态安全进行了评价。结果表明：自黑河上游至下游,生态安全状况依次降低。肃南县和祁连县草原生态安全;民乐县和高台县较安全;山丹县稍不安全;肃州区、甘州区和嘉峪关市不安全;金塔县、临泽县和额济纳旗极不安全。各县区对不同因子的敏感程度也各不相同。图2,表4,参8。