地理研究 ›› 2010, Vol. 29 ›› Issue (5): 935-946.doi: 10.11821/yj2010050018

• 环境与生态 • 上一篇    下一篇

崇明东滩湿地CO2 、CH4和N2O 排放的时空差异

汪青1,2, 刘敏2, 侯立军3, 程书波2,4   

  1. 1. 安徽师范大学国土资源与旅游学院,芜湖 241003;
    2. 华东师范大学地理系,地理信息科学教育部重点实验室,上海 200062;
    3. 华东师范大学河口海岸国家重点实验室,上海 200062;
    4. Department of Environmental Geosciences, Center for Earth Sciences, Vienna University, Althanstrasse 14, 1090 Vienna, Austria
  • 收稿日期:2009-05-16 修回日期:2009-09-26 出版日期:2010-05-20 发布日期:2010-05-20
  • 作者简介:汪青(1982-),男,安徽泾县人,讲师。主要从事河口湿地生物地球化学和温室气体排放研究。 E-mail:ahnuwq@mail.ahnu.edu.cn
  • 基金资助:

    国家自然科学基金项目(40671171);安徽师范大学青年基金项目(2008xqn68)

Characteristics and influencing factors of CO2, CH4 and N2O emissions from Chongming eastern tidal flat wetland

WANG Qing1,2, LIU Min2, HOU Li-jun3, CHENG Shu-bo2,4   

  1. 1. Department of Geography, Anhui Normal University, Wuhu 241000, Anhui, China;
    2. Department of Geography, Key laboratory of Geo-information of the Ministry of Education, East China Normal University, Shanghai 200062, China;
    3. State Key Laboratory of Estuarine and Coastal Research, Shanghai 200062, China;
    4. Department of Environmental Geosciences Center for Earth Sciences, Vienna University, Althanstrasse 14, 1090 Vienna, Austria
  • Received:2009-05-16 Revised:2009-09-26 Online:2010-05-20 Published:2010-05-20

摘要:

通过静态暗箱—气相色谱法研究了长江口崇明东滩四类典型湿地(围垦湿地、高潮滩、中潮滩和低潮滩)CO2、CH4和N2O排放特征及影响因素。结果表明,在生长季尺度下,CO2、CH4和N2O均以排放为主;在昼夜尺度下,CO2和CH4在夜间排放量大于白昼排放量,而N2O的排放高峰出现在下午;在潮水退去、潮滩暴露初期,CH4和N2O有大量排放,CO2正好相反。崇明东滩温室气体排放通量自岸向海有明显的梯度变化,总体趋势是越近岸通量值越大。观测与实验表明,温度、潮汐、土壤理化性质、植物和土地利用变化都对温室气体排放通量有明显的影响,其中滨海潮滩湿地特有环境因子潮汐以"淹没—暴露"光滩沉积物的方式控制温室气体的排放。

关键词: 二氧化碳, 甲烷, 氧化亚氮, 温室气体排放, 河口滨岸湿地, 长江口

Abstract:

The temporal and spatial variations and effect factors of greenhouse gases (CO2, CH4 and N2O) emission from Chongming eastern tidal flat, the typical and most important wetland of the Yangtze estuary, have been studied on three time scales, i.e. seasonally, diurnally and tidally, and at four sampling areas, i.e. reclaimed wetland, high tidal flat, middle tidal flat and low tidal flat. On the scale of growing season, all of the gases emitted significantly from wetland. Diurnal fluxes of CO2 and CH4 were less than nocturnal ones, and N2O flux peak was found in the afternoon. In the early stage of the exposure after tide ebbed, CH4 and N2O emitted from sediments, while CO2 was absorbed by sediments. The spatial variation of greenhouse gases was related to water gradient along the direction from land to sea. CH4 emission from high tidal flat was significantly higher than that from reclaimed wetland and from middle tidal flat, and a slight consumption was observed at low tidal flat. N2O emitted only at reclaimed wetland and consumed at other sampling sites. CO2 showed a significant emission from the planted sites and a slight consumption at low tidal flat. Both air temperature and soil temperature exerted influence on gases emission, with plants as intermediary. Tide-caused "immergence-exposure" change in sediment proved to be indispensable to gases emission from tidal wetlands. Physic-chemical characteristics of soil, such as organic carbon, ammonium, sulfate and redox potential, had profound effects on gases emission. Cutting of plants led to consequent additional emission. Land use change caused change of gases emission: as high tidal flat was converted into reclaimed wetland, flux of CH4 decreased and fluxes of N2O and CO2 increased. The estimated emissions in growing season from the Chongming eastern tidal flat wetland were 5.1×107 g CH4, 1.0×105 g N2O and 1.7×1011 g CO2, respectively.

Key words: carbon dioxide, methane, nitrous oxide, greenhouse gas emission, coastal wetland, Yangtze estuary