"Subsurface methane dynamics of fens: Biogeochemical controls on production, peat free-phase gas content and efflux"

泥炭地是加拿大重要的生态系统，约占该国陆地面积的12%。这些生态系统在全球碳循环中发挥着重要作用，占全球土壤碳储量的三分之一，占温室气体甲烷（CH4）大气排放量的10%。尽管这一重要作用，泥炭地CH4通量的时空格局仍然描述得相当少，这可能是因为沸腾（气泡释放）对总CH4通量的贡献。如果沸腾是重要的，这也表明气泡（自由相气体；FPG）存在于泥炭土中。近十年来的研究表明，泥炭地中FPG的存在及其重要性；然而，对于富含矿物质的泥炭地的FPG以及沸腾对这些生态系统总CH4通量的相对重要性知之甚少。这些富含矿物质的泥炭地（沼泽）具有不同的植被群落，因此具有不同的土壤结构，这表明FPG的CH4生产，运输和捕获速率可能与以泥炭为主的泥炭地有很大不同。该研究计划旨在通过以下方法解决这一知识空白：1)确定几种泥炭沼泽中溶解CH4的储量，2)描述该储量大小的时空变化，3)评估沸腾对这些泥炭沼泽总CH4通量的重要性，4)评估对CH4储量和沸腾的潜在控制。

Peatlands are important ecosystems in Canada, covering approximately 12% of the country's landmass. These ecosystems play an important role in the global carbon cycle, accounting for up to one third of global soil carbon stock and up to 10% of atmospheric emissions of the greenhouse gas methane (CH4). Despite this important role, spatial and temporal patterns of CH4 fluxes from peatlands are still fairly poorly described, likely because of the contribution of ebullition (release of bubbles) to total CH4 flux. If ebullition is important, this also suggests that bubbles (free-phase gas; FPG) are present within peat soil. Research over the past decade has indicated the presence and importance of FPG in Sphagnum-dominated peatlands; however, very little is known about FPG in more mineral rich peatlands and the relative importance of ebullition to total CH4 flux from these ecosystems. These mineral rich peatlands, fens, have a different vegetation community, and hence soil structure, suggesting that the rate of CH4 production, transport and trapping of FPG may be very different than Sphagnum-dominated peatlands. The proposed research program aims to address this gap in knowledge by 1) determining the stock of CH4 dissolved, and as FPG in several fen peatlands, 2) describing the spatial and temporal variation in the size of this stock, 3) evaluating the importance of ebullition to the total CH4 flux from these fens, and 4) evaluating potential controls on CH4 stock and ebullition.