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.     

汽车污染与控制探讨

通过阐述汽车污染的原理，提出了汽车的防污途径有控制汽车尾气污染的方法。     

纳米材料对环境和健康的潜在危害

随着越来越多的纳米商品材料在生产和生活中的应用，纳米材料的环境安全问题逐渐引起关注，纳米科技和纳米材料的潜在风险及其负面影响已成为专家共识。文章综述了纳米材料对环境和生命健康带来的可能危害及其毒性特性，并认为深入研究纳米材料的环境安全问题将有助于建立正确生产，使用和处理纳米材料的科学规范。     

Cells of the connective tissue differentiate and migrate into pollen sacs

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.     

海岸带环境综合管理问题探讨

目前,中国海岸带环境管理中存在的法律、组织协调和运行机制等现有主要问题;福建省海岸带环境管理中存在的主要问题,提出了调整海洋环境功能区划、建立海洋污染事故快速反应体系与应急联动处置机制、加快城市排海污水处理能力的规划与建设、规范海水养殖功能区的管理、加强污染物排海总量控制技术与政策研究、实施海湾区域开发规划环境影响评价、实施海陆一体化的海岸带环境综合管理等福建省海岸带环境综合管理的调控措施.     

层状云清除气溶胶的数值模拟

建立了一个一维层状云系的气溶胶清除模式,模式旨在模拟云发展过程中云、雨水中气溶胶浓度的时空演变规律,研究气溶胶粒子的云内清除和云下清除的相对贡献大小及其湿沉降速率等.模拟结果在一定程度上与实测结果相符.     

环境物质拟除虫菊酯毒理学研究进展

拟除虫菊酯作为一种重要的合成杀虫剂,在人们的生产生活中有着广泛的应用,但同时其毒理学问题也越来越引起人们的注意,许多学者对此进行了深入的研究,在此研究基础上,从对动物的神经毒性、生殖毒性和生理生化毒性三个方面,对拟除虫菊酯的毒理学研究进展作一综述.     

BP人工神经网络预测邻苯二甲酸酯光化学降解

将反向传播人工神经网络（BP－ANN）用于邻苯二甲酸酯类化合物的光化学降解的预测中，选取正交设计的试验点作为反向传播人工神经网络的训练集，实现对全实验域试验点的预测，并与实测的试验数据比较。结果表明反向传播人工神经网络（BP－ANN）具有良好的预测能力。     

入冬水生高等植物的衰亡对河流水质的影响

上海市郊河流水体中有很高的氮、磷和有机负菏，由于受水生高等植物生灭的影响，初春河流中的氮、磷和有机负菏明显高于上一年的初冬，河流中的水生高等植物能大量地吸收水体中的氮、磷，抑制藻类生长，净化水质；但其植株残体在水中的腐解，又会重新释出营养元素，造成对水体的二次污染。在冬季，随着水生高等植物的大量死亡这种污染更加明显，应加强对水生高等植物的利用，尝试建立既能净化水质，又有创造经济效益的生态工程模式，使市郊受污水体得到资源化利用。