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301.
Nalinee Thongtham Erik Kristensen Som-Ying Puangprasan 《Estuarine, Coastal and Shelf Science》2008,80(4):573-580
Field measurements on leaf removal by populations of sesarmid crabs at different locations in the Bangrong mangrove forest, Phuket, Thailand, indicated that crabs on average can remove 87% of the daily leaf litter fall by ingestion or burial. The removal rate is correlated positively with the number of crab burrows and negatively with tidal inundation time. The results from the field were supplemented with observations on the behavior of Neoepisesarma versicolor in laboratory microcosms and a mangrove mesocosm. N. versicolor feeds primarily at night and total time spent feeding was up to an order of magnitude higher in the artificial microcosms than under simulated in situ conditions in the mesocosm. Most of the time during both day and night was spent resting near the entrance or inside burrows. N. versicolor mainly feeds on mangrove leaves and scraps of food material from the sediment surface. This is supported by examinations of stomach content, which showed that 62% is composed of higher plant material and 38% of detritus and mineral particles from the sediment. The nutritive value of leaves and detritus is insufficient to maintain crab growth. Sesarmid crabs may instead obtain the needed nutrients by occasional consumption of nitrogen-rich animal tissues, such as carcasses of fish and crustaceans, as indicated by the presence of animal remains in the stomach and the willingness of crabs to consume fish meat. Laboratory experiments on leaf consumption and leaf preferences of N. versicolor indicate that they preferentially feed on brown leaves, if available, followed by green and yellow leaves. If all species of sesarmid crabs in the Bangrong mangrove forest consume leaves at the same rate as N. versicolor, they could potentially ingest 52% of the total litter fall. 相似文献
302.
气井合理产能是凝析气藏开发的一项重要指标,关系到气藏的开发水平和经济效益。在深入分析红台凝析气田开采特征的基础上,运用最小携液产气量、一点法、类比法、数值模拟法等多种方法开展气藏合理产能研究。首次给出适合红台凝析气田的一点法计算公式,论证红台凝析气田合理产能为1.0×10^8m^3。 相似文献
303.
The purification law of nitrogen in Deyeuxia angustifolia,Carex lasiocarpa and Deyeuxia angustifo-lia-Carex lasiocarpa combined wetland systems in the Sanjiang Plain,China was studied by field simulation experi-ment.The results indicate that the removal rates of TN,NH4+-N and NO3--N in above three types of wetlands present an obvious logarithm growth trend along with the time.There are evident removal effects for NH4+-N and NO3--N in water bodies of wetlands after the 30th day of experiment,with the removal rates over 80.0%,but the removal rate of TN is slightly low,being 63.1%-74.3%.NO3--N is most quickly removed by the combined wetland,and NH4+-N by Deyeuxia angustifolia wetland.The removal speeds of TN by the three wetland systems are comparatively slow,of which the Deyeuxia angustifolia wetland is the fastest.In consideration of plant growth season,Deyeuxia angustifolia wetland has much more practical application value in purifying nitrogen.These results can provide references for the study on the purification function of wetlands and the control of non-point source pollution in Northeast China. 相似文献
304.
以新型间歇增氧垂直流人工湿地系统为研究对象,采用中心复合设计响应曲面法优化垂直流人工湿地脱氮处理过程中曝气工艺参数并预测其脱氮效能。以曝气量、曝停比、曝停周期为间歇曝气影响因素,分别以人工湿地氨氮去除率和总氮去除率为响应值建立垂直流人工湿地氨氮去除率和总氮去除率的二次回归模型,通过假设检验(F-test),模型均非常显著且具有较好的相关性。间歇增氧垂直流人工湿地脱氮处理中曝气量、曝停比为对氨氮去除影响极显著的曝气参数,通过影响因子主次分析,曝气量、曝停比、曝停周期对氨氮去除率的影响顺序是:曝停比>曝气量>曝停周期;曝停周期为对总氮去除具有极显著影响的曝气参数,通过影响因子主次分析,曝气量、曝停比、曝停周期对TN去除率的影响顺序是:曝停周期>曝气量>曝停比。模型预测氨氮与总氮去除率的最佳曝气参数分别为:曝气量2 m3/h、曝停比0.25、曝停周期12 h、曝气量2 m3/h、曝停比0.25、曝停周期6 h;氨氮、总氮去除率预测值分别为98.4%、83.2%,预测值与实测值吻合。响应曲面法用于优化曝气参数对人工湿地脱氮效能影响具有可行性,可实现间歇增氧人工湿地脱氮效能的准确预测。 相似文献
305.
306.
人工湿地脱氮除磷的效果与机理研究进展 总被引:38,自引:4,他引:38
人工湿地作为一种低耗高效的污水处理系统正在被广泛应用于各种类型的污水处理,不仅对有机污染物有较强的降解能力,而且对传统的二级处理难以去除的氮磷也有较好的去除效果。人工湿地污水处理系统是一个复合生态工程系统,其对污染的去除机理是一个错综复杂的过程,基质、水生植物和微生物共同发挥着重要作用。综述了人工湿地脱氮除磷的效果与机理,讨论了基质、水生植物、微生物及其他外界因素对系统处理效果的影响及氮磷去除的预测模型,提出了当前人工湿地研究中存在的问题和提高人工湿地脱氮除磷能力的对策。 相似文献
307.
Alan L. Dick 《Journal of Atmospheric Chemistry》1990,11(1-2):179-196
A model has been set up to investigate the wet and dry aerosol removal processes which occur in clean air over the Antarctic Peninsula. Input for the model was obtained from bulk chemical analysis and scanning electron microscopy of aerosol and snow samples collected simultaneously at remote sites around the Peninsula. The model predicts that sulphate and sea-salt aerosol will be removed mainly in-cloud by riming of falling snow and ice crystals. Crustal aerosol is principally removed by acting as nuclei for these crystals and by impaction on falling snow. For the largest, locally-generated aerosol dry deposition is indicated as the major removal process. These findings suggest a possible mechanism for the observed air/snow fractionation. 相似文献
308.
在模拟含Zn2 废水中加入Mg2 和Al3 ,以NaOH为沉淀剂,研究金属盐水解即时合成层状双氢氧化物(LDH)去除Zn2 的可行性。详细探讨了体系终点pH值、配料中Mg2 /Zn2 摩尔比值及反应温度和时间对Zn2 去除率的影响,结合X射线衍射分析(XRD)探讨了Zn2 去除机理,并与化学沉淀法进行了比较。结果表明,实验条件下只有pH值显著影响Zn2 去除率(p<0.05),在9.0~11.0范围内去除效果最佳,达99%以上。通过XRD分析结合即时合成法特点,废水中Zn2 主要是在晶体生成阶段以Zn-Mg-Al三元LDH化合物形式被去除的。与化学沉淀法相比,即时合成法效果更好,适用pH值范围更广,用来处理含Zn2 废水更具优势。 相似文献
309.
310.
利用美国新一代中尺度WRF(weather research and forecasting)模式,采用双向二重嵌套网格技术,对2005年7月1—2日山西的大暴雨天气过程进行数值模拟,并利用模式输出的高分辨率动力协调资料进行了初步诊断分析,着重分析了排熵指数与暴雨区的关系。结果表明:活跃的副高是造成此次强降水的主要影响系统,低空西南风急流为暴雨提供了充足的水汽及动力条件;大气排熵指数由高值向低值的演变有利于对流的发展,从而导致对流暴雨形成;负熵变区(IRE<0)对应着暴雨区,负熵变区的汇合反映了暴雨的落区;排熵指数与暴雨区有较好的对应关系。 相似文献