海岸带环境过程实验室知识库

(1) 中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室

Salt marshes are coastal wetlands that are considered to be a potential natural source of methane ( CH_4 ). By controlling the production, oxidation, and transport of CH_4 in soils, tidal action drives the episodic and high-magnitude emissions of CH_4 from coastal wetlands. Using the eddy covariance technique, we measured the CH_4 fluxes, environmental factors,and tidal dynamics in a salt marsh in the Yellow River Delta in China. We aimed to investigate the dynamics of CH_4 emissions in the growing season and to analyze the effect of tidal action on CH_4 emission. The results showed that the mean daily methane was 0.063 mg m~(-2) h~(-1),ranging from -0.36 to 0.57 mg m~(-2) h~(-1),during the growing season. Tidal flooding and the wet stage after tides are the significant sources of CH_4. Drying and wetting cycles induced by short-term tides resulted in pulsed CH_4 emissions. Therefore, the soil drought and wetting induced by increasing temperatures and precipitation distribution under climate change will positively impact CH_4 emissions and the carbon cycle in the region.

盐沼湿地作为陆海交互作用的过渡带是CH_4重要的自然来源。潮汐活动通过影响CH_4的产生、氧化和传输驱动了湿地CH_4间歇性、周期性的排放。利用涡度相关和微气象监测技术,对黄河三角洲一个盐地碱蓬生态系统CH_4通量、环境因子和水文要素(潮汐)进行了长期连续监测分析了该生态系统生长季CH_4排放的季节动态及潮汐作用对CH_4排放的影响。结果表明:生长季该生态系统是CH_4的排放源,排放日均值为0.063 mg m~(-2) h~(-1),(范围为-0.360.57 mg m~(-2) h~(-1))。潮汐淹水阶段和落潮后湿润阶段表现为CH_4的显著源。此外我们发现,短期潮汐活动引起土壤干湿状况的变化促进了CH_4脉冲式的排放,因此未来气候变化下温度升高和降雨季节分配引起的土壤干湿变化将会对该区域CH_4排放甚至碳循环产生积极影响。