大别山超高压变质杂岩的折返

作为世界上规模最大的一个超高压变质带，大别山超高压变质杂岩是扬子板块 与中朝板块在三叠纪碰撞造山的产物，表现为扬子板块呈北北东向斜向俯冲到中朝板块之下。 超高压变质杂岩的折返机制是个复杂的动力学过程，折返速率也随时间推移而变慢。早期阶段 （三叠纪－早侏罗纪）同碰撞期浮力驱动下高压－超高压变质杂岩在俯冲带内沿道冲－韧性剪 切断裂快速挤侵（ｅｘｔｒｕｓｉｏ）到地壳层位，折返速率高达４ｍｍ／年；中期伴随着巨厚造山带山根的 拆沉，上部发生拉张塌陷，使超高压变质杂岩进一步减压，但折返速率缓慢，～(４０)Ａｒ／~(３９)Ａｒ年代学显 示１１７Ｍａ前它们仍处在地壳的较深部；晚期伴随着晚侏罗－早白垩纪花岗质岩浆的上升侵位， 超高压变质杂岩进一步抬升，同时低角度正断层发育，此阶段的折返机制类似于变质核杂岩模 型。整个折返过程中剥蚀一直在起作用。     

A Simulation of Temporal and Spatial Variations in Carbon at Landscape Level: A Case Study for Lake Abitibi Model Forest in Ontario,Canada

Using a case study of the Lake Abitibi Model Forest (LAMF), this study aims to assess the temporal and spatial variability in carbon storage during 1990–2000, and to present a comprehensive estimation of the carbon budget for LAMF's ecosystems. As well, it provided the information needed by local forest managers to develop ecological and carbon-based indicators and monitor the sustainability of forest ecosystems. Temporal and spatial carbon dynamics were simulated at the landscape level using ecosystem model TRIPLEX1.0 and Geographical Information System (GIS). The simulated net primary productivity (NPP) and carbon storage in forest biomass and soil were compared with field data and results from other studies for Canada's boreal forests. The results show that simulated NPP ranged from 3.26 to 3.34 tC ha⁻¹ yr⁻¹ in the 1990s and was consistent with the range measured during the Boreal Ecosystem-Atmosphere Studies (BOREAS) in central Canada. Modeled NPP was also compared with the estimation from remote sensing data. The density of total above-and belowground biomass was 125.3, 111.8, and 106.5 tC ha⁻¹ for black spruce, trembling aspen, and jack pine in the LAMF ecosystem, respectively. The total carbon density of forested land was estimated at 154.4 tC ha⁻¹ with the proportion of 4:6 for total biomass and soil. The analysis of net carbon balance of ecosystem suggested that the LAMF forest ecosystem was acting as a carbon sink with an allowable harvest in the 1990s.     

Effect of free-air CO2 enrichment on nematode communities in a Chinese farmland ecosystem

At a rice-wheat rotational free-air CO2 enrichment(FACE) platform, the effect of elevated atmospheric CO2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO2 (ambient 370 μl/L 200 μl/L).32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO2 may indicate the change of soil food web.     

生态系统服务的核算方法

生态系统服务是指对人类生存及生活质量有贡献的生态系统产品和生态系统功能 ,包括由自然生态过程产生并维持的环境和资源条件。目前已有的生态系统服务核算方法可以分为市场价值法、替代市场法和假想市场法。     

Effects of atmospheric mercury pollution on terrestrial ecosystem in Chongqing, China

1　ＩｎｔｒｏｄｕｃｔｉｏｎＭｅｒｃｕｒｙ(Ｈｇ)ａｓａｇｌｏｂａｌｐｏｌｌｕｔａｎｔｈａｓｃａｕｓｅｄｃｏｎｃｅｒｎｗｏｒｌｄｗｉｄｅｓｉｎｃｅｔｈｅｅｎｄｏｆ 1980ｓ.Ｉｔｉｓｅｍｉｔｔｅｄｔｏｔｈｅａｔｍｏｓｐｈｅｒｅｆｒｏｍｂｏｔｈａｎｔｈｒｏｐｏｇｅｎｉｃａｎｄｎａｔｕｒａｌｓｏｕｒｃｅｓ.Ｉｍｐｏｒｔａｎｔｓｏｕｒｃｅｏｆｔｈｅｆｏｒｍｅｒｉｓｔｈｅｄｉｓｃｈａｒｇｅｆｒｏｍ ｐｒｏｄｕｃｔｉｏｎａｎｄｕｓｅｏｆＨｇａｓｗｅｌｌａｓｔｈｅｃｏｍｂｕｓｔｉｏｎｏｆｆｏｓｓｉｌｆｕｅｌｓ(Ｎｒｉ…     

我国水产养殖业对环境的影响及对策

综述了我国水产养殖业的自身污染、对水环境和生态系统的影响及其对景观环境质量的影响等，提出应在健全的法律法规指导下，建立完善的水产养殖环境管理系统，加强营养与饲料学研究，提高水产养殖饲料质量和投饵水平，同时强化环境工程技术在集约化水产养殖中的应用，以减少污染排放，使水产养殖走可持续发展的道路。     

热液中金的沉淀机理研究综述

金的沉淀机理是了解热液金矿床成矿机制的关键。本文总结了金从热液中沉淀机理的最新研究成果，介绍了各种主要含金配合物的溶解度拨制机制，阐述了矿物表面吸附／还原以及电化学富集等矿物表面作用对金沉淀行为的制约。     

石英表面配合物与溶解动力学模型

阐述了石英表面配合物和溶解动力学机理之间的关系，指出了石英的反应性主要受负电性表面物种的控制，从而导致电解质、离子强度、pH等因素对石英溶解的催化效应．溶解达率的提高与反应活化能的降低成活化熵的增大有关。最后，介绍了在过渡态理论和表面反应模型基础上建立的石英溶解速率方程。     

浅析生态系统平衡及其意义

文章简要论述了生态系统的组成、影响生态系统平衡的自然因素和人为因素.生态系统平衡与失衡在自然环境中作用及其意义.生态系统是由各类生物共同组成的生物群落(bioflora)或生物系统(living things'system)与环境系统构成的具有一定结构和功能的一个不断更新和变化的开放系统.但是,生态系统这种维护自身相对平衡的能力是有条件、有一定限度的,或者说,对平衡的干扰不能超过系统本身的遭受极限,否则就会使破坏后的生态系统难于恢复到原来的平衡状态.     

喀斯特石漠化地区生态恢复重建技术及其成果的价值评估——以广西平果县果化示范区为例

用土壤改良技术、表层岩溶水开发技术和生物恢复重建技术等对广西平果县果化示范区的土壤和植被等进行了恢复重建,结果是:果化示范区的植被覆盖率由2000年重建前的10%提高到2005年的50%~70%,水土流失也得到了较明显的控制,土壤侵蚀模数下降到了510.92 kg/(km2.a)。用生态经济学的原理和方法,对恢复后的生态系统服务价值进行了评估,结果表明示范区新增的间接利用价值达10186873元,间接利用价值是直接利用价值的12倍。新增的生态效益为8002053元,社会效益为2184820元。扣除治理期间实际投入的科研费用,增加的总生态服务净价值为8869308元。