• 关键词：盐度  间隙水  溶解性CH₄  河口湿地  短叶茳芏

• 基金项目：国家自然科学基金（No.41371127）；福建省基本科研专项重点项目（No.2014R1034-1）；福建师范大学校级创新团队项目（No.IRTL1205）

• 何露露
• 1. 福建师范大学地理科学学院, 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. 福建师范大学亚热带湿地研究中心, 福州 350007

• 黄佳芳
• 1. 福建师范大学地理科学学院, 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. 福建师范大学亚热带湿地研究中心, 福州 350007

• 谭立山
• 1. 福建师范大学地理科学学院, 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. 福建师范大学亚热带湿地研究中心, 福州 350007

• 仝川
• 1. 福建师范大学地理科学学院, 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. 福建师范大学亚热带湿地研究中心, 福州 350007

• 摘要：以闽江河口区塔礁洲河岸分布的短叶茳芏（Cyperus malaccensis）淡水感潮沼泽湿地及其比邻的光滩为研究对象，通过采集土芯和土壤-植物连续体，构建中型生态系统（Mesocosm），并2016年12月-2017年10月模拟持续恒定盐度增加及波动短期盐度增加两种情景，测定间隙水溶解性甲烷（CH₄）浓度及其它理化因子，探讨持续恒定和短期波动盐度增加对河口淡水感潮湿地间隙水溶解性CH₄浓度的影响.结果表明：①2种处理均显著抑制了短叶茳芏沼泽及光滩湿地间隙水溶解性CH₄浓度，波动盐度对于短叶茳芏湿地间隙水溶解性CH₄浓度的抑制效果明显高于光滩；②恒定盐度及波动盐度增加主要通过提高间隙水SO₄^2-、Cl^-、NH₄⁺-N和TN浓度，降低间隙水pH值，抑制间隙水溶解性CH₄浓度；③短叶茳芏沼泽间隙水溶解性CH₄浓度受间隙水pH值影响最为显著，而光滩间隙水溶解性CH₄浓度则受间隙水NH₄⁺-N浓度及气温影响显著.研究表明，未来盐水入侵情景下，河口淡水感潮湿地间隙水溶解性CH₄浓度将下降，且在盐度短期增加情景下，河口淡水感潮沼泽湿地间隙水溶解性CH₄浓度下降幅度大于光滩湿地.

• Abstract：The effects of the persistent constant salinity and short-term fluctuating salinity increases on porewater dissolved CH₄ and other physical and chemical factors were determined via the mesocosm method. The mesocosm had been manipulated by collecting soil core and soil-plant continuum from the riparian freshwater tidal Cyperus malaccensis marsh and non-vegetated mudflat in the Tajiaozhou in the Min River estuary. The control treatment and constant salinity increase treatment was 0‰ and 10‰, respectively, and the fluctuating salinity increase treatment was three weeks of freshwater with 0‰ and then one week of saltwater of 10‰ during each one month cycle from December 2016 to October 2017. The results showed that:① the two types of salinity raise treatments all had the significant inhibitory effect on the porewater dissolved CH₄ concentration of the C. malaccensis marsh and the mudflat, while the short-term fluctuating salinity had a significantly higher inhibitory on the C. malaccensis marsh than on the mudflat;②the two types of salinity raise treatments inhibited the porewater dissolved CH₄ concentration mainly caused by the increasement of the porewater SO₄^2-, Cl^-, NH₄⁺-N and TN concentration, and the decrease of pH;③the porewater dissolved CH₄ concentration in C. malaccensis marsh was most affected by the porewater pH, while the porewater dissolved CH₄ concentration in the mudflat was significantly affected by the porewater NH₄⁺-N concentration and temperature. Our results indicated that saltwater intrusion in future will decrease the porewater dissolved CH₄ concentration in both estuarine freshwater tidal, marsh and bare mudflat, and the decrease of porewater dissolved CH₄ concentration in freshwater tidal marsh is greater than that in bare mudflat under the short-term fluctuating salinity increase.

• Key words：salinity  porewater  dissolved CH₄  estuarine marsh  Cyperus malaccensis

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