Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA.
Institute of Soil Science, Center for Earth System Research and Sustainability (CEN), Universität Hamburg, 20146, Hamburg, Germany.
Nat Commun. 2020 Oct 14;11(1):5154. doi: 10.1038/s41467-020-18763-4.
Blue carbon (C) ecosystems are among the most effective C sinks of the biosphere, but methane (CH) emissions can offset their climate cooling effect. Drivers of CH emissions from blue C ecosystems and effects of global change are poorly understood. Here we test for the effects of sea level rise (SLR) and its interactions with elevated atmospheric CO, eutrophication, and plant community composition on CH emissions from an estuarine tidal wetland. Changes in CH emissions with SLR are primarily mediated by shifts in plant community composition and associated plant traits that determine both the direction and magnitude of SLR effects on CH emissions. We furthermore show strong stimulation of CH emissions by elevated atmospheric CO, whereas effects of eutrophication are not significant. Overall, our findings demonstrate a high sensitivity of CH emissions to global change with important implications for modeling greenhouse-gas dynamics of blue C ecosystems.
蓝碳（C）生态系统是生物圈中最有效的碳汇之一，但甲烷（CH）排放可能会抵消其气候冷却效应。蓝碳生态系统中 CH 排放的驱动因素以及全球变化的影响还知之甚少。在这里，我们测试海平面上升（SLR）及其与大气 CO 升高、富营养化和植物群落组成相互作用对河口潮汐湿地 CH 排放的影响。CH 排放随 SLR 的变化主要受植物群落组成和相关植物特性的变化所介导，这些特性决定了 SLR 对 CH 排放的方向和幅度的影响。此外，我们还发现大气 CO 升高强烈刺激了 CH 排放，而富营养化的影响则不显著。总的来说，我们的研究结果表明，CH 排放对全球变化高度敏感，这对蓝碳生态系统温室气体动态建模具有重要意义。
