东北三江平原土壤氧化CH4研究

三江平原土壤不同深度氧化大气浓度CH4和高浓度CH4的速率具有明显的垂直差异 .2个非淹水土壤整个剖面都具有氧化大气浓度CH4的潜力 ,以表层土的速率为最大 .非淹水的耕作土壤残留的有机质层仍保留了较强的氧化大气浓度CH4潜力 ,氧化CH4速率是耕作层的 2 0倍 .淹水土壤的大部分层次不具有氧化大气浓度CH4的潜力 .所有供试土壤均能消耗高浓度CH4,泥炭含量较高的土壤层次比矿质层氧化高浓度CH4的速率高     

金鱼(Carassius auratus L.)对水中游离态铅的吸收积累及鳃分泌粘液的自身保护作用

研究了金鱼（ Ｃａｒａｓｓｉｕｓａｕｒａｔｕｓ Ｌ．） 在铅暴露实验中的铅吸收过程及鱼鳃分泌物的自身保护作用、水相Ｐｂ２＋ 的鳃吸收机理以及分泌粘液对铅的络合作用．结果表明，金鱼因铅暴露导致粘液分泌量增加．结合到鳃上的铅与水相Ｐｂ２＋ 活度关系可用Ｌａｎｇｍｕｉｒ 吸附等温式表述．据此估算的最大结合量为０－９４２４ ｍ ｍｏｌ／ｋｇ（干重） ．非常接近１ 的Ｈｉｌｌ 常数（１－０１２）说明金鱼鳃上仅有一种类型的Ｐｂ２＋ 结合位点．平均每尾金鱼鳃上Ｐｂ２＋ 的结合位点数达１－６２ ×１０－ ５ ｍ ｍｏｌ，结合的条件稳定常数（ｌｏｇ ＫＰｂ鳃） 为４－８ ．血液铅含量与鳃铅含量间呈显著线性关系．金鱼吸收Ｐｂ２＋ 的主要过程为：Ｐｂ２＋ 结合到鳃上，其后被动扩散或载体转运穿过鳃上皮，进入血液循环．     

Low intensity ultrasound stimulates biological activity of aerobic activated sludge

This work aims to explore a procedure to improve biological wastewater treatment efficiency using low intensity ultrasound. The aerobic activated sludge from a municipal wastewater treatment plant was used as the experimental material. Oxygen uptake rate (OUR) of the activated sludge (AS) was determined to indicate the changes of AS activity stimulated by ultrasound at 35 kHz for 0–40 min with ultrasonic intensities of 0–1.2 W/cm². The highest OUR was observed at the ultrasonic intensity of 0.3 W/cm² and an irradiation period of 10 min; more than 15% increase was achieved immediately after sonication. More significantly, the AS activity stimulated by ultrasound could last 24 h after sonication, and the AS activity achieved its peak value within 8 h after sonication, or nearly 100% higher than the initial level after sonication. Therefore, to improve the wastewater treatment efficiency of bioreactors, ultrasound with an intensity of 0.3 W/cm² could be employed to irradiate a part of the AS in the bioreactor for 10 min every 8 h. Translated from Environmental Science, 2005, 26(4): 124–128 [译自: 环境科学]     

假单胞菌摄磷和释磷条件的研究

考察了碳、硫等物质对废水生物脱磷优势菌假单胞菌磷代谢的影响．结果表明，缺磷环境导致假单胞菌产生过量摄磷现象；假单胞菌无论是经过无碳厌氧、无碳好氧还是无硫厌氧、无硫好氧培养后，转接到富磷培养基内好氧培养时，都产生过量摄磷现象．随着在富磷培养基内的好氧培养时间延长，细菌的摄磷量下降．     

NTA和DTPA对小麦幼苗对金属吸收的诱导效应

通过盆栽试验和化学提取实验研究了有机配体NTA和DTPA对小麦对沙土中外源重金属Cd,Cu,Pb和Zn的吸收的影响.研究表明,在所试验的土壤金属浓度下,有机配体NTA和DTPA的添加均明显导致小麦幼苗中金属Cu,Zn,Cd和Pb富集量的增加,且DTPA的作用效果高于NTA.10mmol·kg-1DTPA作用效果高于5mmol·kg-1DTPA,但提高程度有限.NTA处理组各金属14 d茎叶富集系数高于7 d茎叶富集系数.对于不同金属,DTPA的作用导致小麦幼苗茎叶富集系数随时间变化的规律不同.5mmol·kg-1NTA,5mmol·kg-1DTPA和10mmol·kg-1DTPA的添加明显导致土壤中4种外源金属的0.01 mol·L-1CaCl2提取态含量的增加.小麦茎叶重金属富集量与0.01mol·L-1CaCl2提取态金属含量具有较好的相关性,说明配体NTA和DTPA的添加导致小麦幼苗对4种金属的富集量的增加是与其导致0.01 mol·L-1CaCl2提取态含量的增加是密切相关的.     

金鱼(Carassius auratus L.)对水中游离态铅的吸收积累及鳃分泌粘液的自身保护作用

研究了金鱼在铅暴露实验中的铅吸收过程及鱼鳃分泌物的自身保护作用，水相Ｐｂ＾２＋的鳃吸收机理以及分泌粘液对铅的络作用。结果表明，金鱼因铅暴露导致粘液分泌量增加。结合到鳃上的铅与水相Ｐｂ＾２＋活度关系可用Ｌａｎｇｍｕｉｒ吸附等温式表述。     

Gene therapy for cystic fibrosis: Will it affect the uptake of prenatal carrier screening?

We report a study which examined whether the decision of 135 couples to accept prenatal cystic fibrosis (CF) carrier screening would be influenced by the advent of gene therapy. A majority (91 couples; 67 per cent) felt that gene therapy for CF would not influence their decision to be screened. Twenty-two couples (16 per cent) stated that they would decline to be screened and an equal number felt ambivalent. Even if the life expectancy of a CF sufferer were increased by gene therapy to normal, 78 per cent of couples would still wish to avail themselves of prenatal carrier screening. A majority of women who decline screening do so because they are opposed to termination of pregnancy. The availability of gene therapy could increase the proportion of couples who accept screening.     

植被对恢复卫生填埋场环境的作用

卫生填埋是目前我国城市生活垃圾处置的主要手段，以城市生活垃圾主要成份的卫生填埋汤，由于来源广，成份复杂，含有大量的易腐有机物和带病原菌的污染物，不可避免地给填埋场周边环境带来一定影响，有些甚至是较严重的影响。     

有机污染物在土壤—水体系中的分配理论

介绍了有机污染物在土壤—水体系中的分配理论。该理论认为有机污染物主要被土壤有机质以非吸附的方式所吸收，所以多种污染物被同时吸收时不存在竞争作用，而且吸收量受到土壤有机质和有机污染物分子极性的影响。有机污染物在土壤有机质—水体系中的分配系数，主要与其水溶性有关。     

Environmental variability and allocation trade-offs maintain species diversity in a process-based model of succulent plant communities

Ecological theory suggests that environmental variability can promote coexistence, provided that species occupy differential niches. In this study, we focus on two questions: (1) Do allocation trade-offs provide a sufficient basis for niche differentiation in succulent plant communities? (2) What is the relative importance of different forms of environmental variability on species diversity and community composition? We approach these questions with a generic, individual-based simulation model. In our model, plants compete for water in a spatially explicit environment. Species differ in their size at maturity and in the allocation of carbon to roots, leaves and storage tissue. The model was fully specified with independent literature data. Model output was compared to characteristics of a species-rich community in the semi-arid Richtersveld (South Africa). The model reproduced the coexistence of plants with different sizes at maturity, the dominance of succulent shrubs, and the level of vegetation cover. We analyzed the effects of three forms of environmental variability: (a) temporal fluctuations in precipitation (rain and fog), (b) spatial heterogeneity of water supply due to run-on and run-off processes and (c) ‘rock pockets’ that limit root competition in space. The three types of variability had differential effects on diversity: diversity exhibited a strong hump-shaped response to temporal variation. Spatial variability increased diversity, with the strongest increase occurring at intermediate levels of temporal variability. Finally, rock pockets had the weakest effect, but contributed to diversity by providing refuges for small species, particularly at low temporal variability. The model thus shows that spatio-temporal variation of resource supply can maintain diversity over long time scales even in small systems, as is the case in the Richtersveld succulent communities. Trade-offs in allocation provide the basis for necessary niche differentiation. By describing resource competition between individual plants, our model provides a mechanistic basis for the link from species traits to community composition at given environmental conditions. It thereby contributes to an understanding of the forces shaping plant communities. Such an understanding is critical to reduce the threats environmental change poses to biodiversity and ecosystem services.