Modeling CH4 and CO2 cycling using porewater stable isotopes in a thermokarst bog in Interior Alaska: Results from three conceptual reaction networks

Quantifying rates of microbial carbon transformation in peatlands is essential for gaining mechanistic understanding of the factors that influence methane emissions from these systems, and for predicting how emissions will respond to climate change and other disturbances. In this study, we used porewater stable isotopes collected from both the edge and center of a thermokarst bog in Interior Alaska to estimate in situ microbial reaction rates. We expected that near the edge of the thaw feature, actively thawing permafrost and greater abundance of sedges would increase carbon, oxygen and nutrient availability, enabling faster microbial rates relative to the center of the thaw feature. (full abstract available in supplemental file 610_NeumannPorewaterExtendedMetadataText.pdf)

定量泥炭地微生物碳转化速率，对于从机制层面阐明调控该生态系统甲烷排放的关键因素，以及预测排放如何响应气候变化与其他干扰过程，均具有至关重要的意义。本研究采集了阿拉斯加内陆一处热融喀斯特沼泽（thermokarst bog）边缘与中心的孔隙水稳定同位素样品，原位估算微生物反应速率。我们推测，在热融地貌（thaw feature）边缘区域，活跃消融的永久冻土以及更高丰度的莎草科植物将提升碳、氧与营养物质的可获得性，进而使该区域的微生物反应速率高于热融地貌中心区域。（完整摘要详见补充文件610_NeumannPorewaterExtendedMetadataText.pdf）