• 关键词：淡水沼泽  微咸水沼泽  反硝化作用  短叶茳芏  闽江口

• 基金项目：福建省科技厅重点项目(No.2013Y0033);国家自然科学基金(No.41371127);福建师范大学校级创新团队项目(No.IRTL1205);福建师范大学地理科学学院研究生科研创新基金项目

• 汪旭明
• 福建师范大学地理科学学院, 福州 350007

• 任洪昌
• 福建师范大学地理科学学院, 福州 350007

• 李家兵
• 1. 福建师范大学地理科学学院, 福州 350007;2. 福建师范大学环境科学与工程学院, 福州 350007

• 仝川
• 1. 福建师范大学地理研究所, 福州 350007;2. 湿润亚热带生态-地理过程教育部重点实验室, 福州 350007;3. 福建师范大学湿地研究中心, 福州 350007

• 摘要：为探讨河口区淡水和微咸水潮汐沼泽湿地沉积物反硝化作用及影响因素,以分布在闽江口道庆洲上的短叶茳芏(Cyperus malaccensis)淡水沼泽湿地和鳝鱼滩上的短叶茳芏微咸水沼泽湿地沉积物为研究对象,运用乙炔抑制培养法测定不同季节的反硝化速率,同时测定沉积物和上覆水理化性质.结果发现,2个短叶茳芏沼泽湿地沉积物反硝化速率均存在明显的季节变化,最高(最低)值分别出现在夏季(秋季)和春季(冬季),温度是影响反硝化速率季节变化的重要因素.道庆洲沉积物反硝化速率((32.72±19.15) μmol·m^-2·h^-1,以N计,下同)显著高于鳝鱼滩((4.97±2.64) μmol·m^-2·h^-1)(p < 0.05).沉积物电导率和上覆水SO₄^2-含量对河口区潮汐沼泽湿地沉积物反硝化速率具有抑制作用,是造成微咸水沼泽湿地沉积物反硝化速率显著低于淡水沼泽湿地的重要因素.沉积物电导率主要通过抑制沉积物对NH₄⁺-N的吸收影响硝化-反硝化耦合作用,进而影响反硝化速率.淡水沼泽湿地反硝化速率对SO₄^2-作用的响应较微咸水沼泽湿地更为敏感.

• Abstract：Comparisons study was conducted to investigate the sediment denitrification rates of tidal freshwater and brackish marshes and the environmental factors influencing on denitrification in sediments by Cyperus malaccensis freshwater marsh in the Daoqingzhou and by C. malaccensis brackish marsh in the Shanyutan of the Min River estuary. Denitrification rate was measured using acetylene inhibition method during four seasons, and the physical and chemical properties of the sediment and overlying water were determined. The sediment denitrification rates of the two marshes demonstrate significant seasonal variation, and the maximum (minimum) values of the two marshes were in summer (autumn) and spring (winter), respectively; temperature was an important controlling factor. The sediment denitrification rate in the freshwater Daoqingzhou site ((32.72±19.15) μmol·m^-2·h^-1) was significantly higher than that in the brackish Shanyutan site ((4.97±2.64) μmol·m^-2·h^-1) (p < 0.05). Sediment conductivity and SO₄^2- concentration of overlying water inhibited sediment denitrification, and are two key factors for a relatively lower denitrification rate in the brackish marsh sediments compared with freshwater marsh. Sediment conductivity affected the nitrification-denitrification coupling with inhibiting the adsorption of NH₄⁺-N by sediment. Sediment denitrification rate in the freshwater marsh demonstrates a more sensitive response to SO₄^2- compared with the brackish marsh.

• Key words：freshwater marsh  brackish marsh  denitrification  Cyperus malaccensis  Min River estuary

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