土地利用变化对湿地景观连通性的影响及连通性优化效应——以江苏盐城海滨湿地为例

土地利用与土地覆盖变化对湿地景观的结构和功能产生深刻的影响。选择江苏盐城海滨地区为研究对象,应用遥感和地理信息系统技术,分析20年来土地利用变化对湿地景观连通性的影响,并以2007年湿地景观生态系统服务功能为基础,采用阻力面模型探讨湿地景观连通性优化途径及其效应。结果显示:①1987—2007年间,盐城海滨区域土地利用结构变化显著。其中耕地面积比重由36.72%上升为46.17%,自然湿地持续减少,面积由44.4%减为26.01%,人工湿地持续增加,面积由9.96%上升为18.72%;②随着区域人类土地利用活动的加强,光滩、碱蓬沼泽和芦苇沼泽的空间连通性降低,区域土地利用导致湿地景观之间生态流阻隔,景观生态服务功能减弱;③2007年湿地景观生态功能强度空间差异显著,以累积耗费距离面、生态源地、耗费路径为依据,对湿地景观连通路径优化结果表明,废黄河口和大丰港附近等关键区域对景观连通性和生态流影响最大,是景观生态节点优化的首要对象;④加强连通路径的关键区域优化、提高景观连通度是实现景观优化的关键。     

Heavy metal （Pb,Zn） uptake and chemical changes in rhizosphere soils of four wetland plants with different radial oxygen loss

Lead and Zn uptake and chemical changes in rhizosphere soils of four emergent-rooted wetland plants; Aneilema bracteatum, Cyperus alternifolius, Ludwigia hyssopifolia and Veronica serpyllifolia were investigated by two experiments: (1) rhizobag filled with “clean” or metal-contaminated soil for analysis of Pb and Zn in plants and rhizosphere soils; and (2) applied deoxygenated solution for analyzing their rates of radial oxygen loss (ROL). The results showed that the wetland plants with di erent ROL rates had significant e ects on the mobility and chemical forms of Pb and Zn in rhizosphere under flooded conditions. These e ects were varied with di erent metal elements and metal concentrations in the soils. Lead mobility in rhizosphere of the four plants both in the “clean” and contaminated soils was decreased, while Zn mobility was increased in the rhizosphere of the “clean” soil, but decreased in the contaminated soil. Among the four plants, V. serpyllifolia, with the highest ROL, formed the highest degree of Fe plaque on the root surface, immobilized more Zn in Fe plaque, and has the highest e ects on the changes of Zn form (EXC-Zn) in rhizosphere under both “clean” and contaminated soil conditions. These results suggested that ROL of wetland plants could play an important role in Fe plaque formation and mobility and chemical changes of metals in rhizosphere soil under flood conditions.     

Characteristics of contaminants in water and sediment of a constructed wetland treating piggery wastewater e uent

Constructed wetland (CW) is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary e uent of livestock wastewater treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil layer and to reduce the phosphorus release from sediments of the free water surface CW for the treatment of secondary piggery wastewater e uent from a livestock wastewater treatment facility. The results revealed that the dominant phosphorus existence types at near the inlet of the CW were non-apatite phosphorus (59%) and residual phosphorus (32%) suggesting that most of the particles of the influent are made up of inorganic materials and dead cells. Sediment accumulation is important when determining the long-term maintenance requirements over the lifetime of CW. Continuous monitoring will be performed for a further assessment of the CW system and design.     

洞庭湖湿地植被演替规律研究

探讨了在构造沉降,泥沙淤积和人类活动三大因素共同作用下,洞庭湖湿地的演替规律,分析了洞庭湖湿地植物群落的自然演替轨迹与洲滩湿地成因的关系.得出结论:洞庭湖洲滩湿地有5种成因,即河相沉积、湖相沉积与河湖相沉积;洞庭湖湿地植物群落的演替表现为三种演替轨迹.     

人工湿地处理系统的研究进展与展望

人工湿地技术作为绿色环保的污水处理新技术,已成为环境科学研究的重要领域之一.本文系统的介绍了人工湿地处理系统的概念、分类及国内外研究和应用现状,指出人工湿地处理系统存在的问题,并展望其进一步发展.     

利用3S技术评价凌河口湿地生态环境质量

基于3S技术,利用中巴地球资源卫星解译数据,于2008年秋季对辽宁省锦州市凌河口湿地自然保护区的土地利用／土地覆盖现状进行野外核查,并结合对湿地进行的鸟类、鱼类、植被状况、空气、水体、土壤状况等调查,采用多样性、代表性、稀有性、自然性、稳定性和人类威胁等6项指标组成的湿地生态环境评价指标体系,对凌河口湿地生态环境质量进行了评价。结果表明,凌河口湿地生态环境处于较好水平。     

不同人工湿地组合净化生活污水效果研究

设计了垂直流＋水平流、水平流＋垂直流、单一水平、单一垂直等4组不同结构的人工湿地组合,研究其对生活污水的净化效果。结果表明：4组人工湿地对CODCr,TP的去除率分别达到80%,70%左右;对TN的去除,垂直＋水平单元去除率最高,为44.30%。     

盘锦市湿地资源利用与恢复生态功能探讨

分析了盘锦市湿地由于不合理的开发利用,导致生态功能受损状况;为防止湿地资源的过度开发,保护湿地生态系统的结构、物种、功能效应,使湿地资源永续利用,提出了具有可操作性的恢复措施。     

硝基苯、苯胺在湿地土壤不同有机组分中的吸附特征

应用平衡法研究了湿地土壤不同有机组分对硝基苯和苯胺的吸附行为.结果表明,吸附等温线经拟合后均符合Freundlich模型,可决系数分别为R2=0.983～0.997,R2=0.963～0.991(P<0.01,n=5),土壤不同有机组分对硝基苯和苯胺的吸附表现为非线性特征,其吸附过程与有机质含量和结构有关.硝基苯和苯胺在湿地土壤中的吸附主要受腐殖酸、易氧化有机质组分和脂类化合物的影响,其中腐殖酸对硝基苯和苯胺具有最大的吸附容量;脂类化合物表现为与硝基苯、苯胺竞争土壤有机质结构中的吸附位点,去除脂类化合物后残余物的吸附量增大;矿物组分对硝基苯和苯胺的吸附是次要的,吸附容量仅为2.31mg·kg-1和3.63mg·kg-1.硝基苯和苯胺的Koc值分别按如下顺序增加:碱提取残余物<原始土<过氧化氢氧化残余物<苯/甲醇提取残余物,原始土<苯/甲醇提取残余物<过氧化氢氧化残余物<碱提取残余物.     

关于壁挂式空调制热舒适性最优出风温度的实验研究

通常,壁挂式房间空调在制热运行时,热风难以落地,导致房间温度分布上热下冷的问题。房间人体主要感受热量的垂直高度为地面0.1 m到1.1 m,经验证,当出风温度在43℃以上时基本不能满足ISO 7730:2005标准要求[1],用户热感效果较差,怎么解决该问题一直困扰各空调企业。本研究对空调制热不同出风温度和速度运行下房间的温度场进行实验研究,结合空气热物理特性,并结合舒适性评价指标,在不增加产品成本的情况下,得出空调制热最优出风温度的实验方法,实现热风落地,提高用户热感效果。