Rising plant‐mediated methane emissions from arctic wetlands

• Published in: Global Change Biology
• Main Authors: Andresen, Christian G., Lara, Mark J., Tweedie, Craig E., Lougheed, Vanessa L.
• Other Authors: National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2016
• Subjects: Arctic; Barrow Peninsula; Arctophila fulva; Barrow; Carex aquatilis; Climate change; Tundra; Alaska
• Online Access: http://dx.doi.org/10.1111/gcb.13469; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.13469; https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.13469; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/gcb.13469; https://onlinelibrary.wiley.com/doi/am-pdf/10.1111/gcb.13469

Abstract Plant‐mediated CH 4 flux is an important pathway for land–atmosphere CH 4 emissions, but the magnitude, timing, and environmental controls, spanning scales of space and time, remain poorly understood in arctic tundra wetlands, particularly under the long‐term effects of climate change. CH 4 fluxes were measured in situ during peak growing season for the dominant aquatic emergent plants in the Alaskan arctic coastal plain, Carex aquatilis and Arctophila fulva , to assess the magnitude and species‐specific controls on CH 4 flux. Plant biomass was a strong predictor of A. fulva CH 4 flux while water depth and thaw depth were copredictors for C. aquatilis CH 4 flux. We used plant and environmental data from 1971 to 1972 from the historic International Biological Program ( IBP ) research site near Barrow, Alaska, which we resampled in 2010–2013, to quantify changes in plant biomass and thaw depth, and used these to estimate species‐specific decadal‐scale changes in CH 4 fluxes. A ~60% increase in CH 4 flux was estimated from the observed plant biomass and thaw depth increases in tundra ponds over the past 40 years. Despite covering only ~5% of the landscape, we estimate that aquatic C. aquatilis and A. fulva account for two‐thirds of the total regional CH 4 flux of the Barrow Peninsula. The regionally observed increases in plant biomass and active layer thickening over the past 40 years not only have major implications for energy and water balance, but also have significantly altered land–atmosphere CH 4 emissions for this region, potentially acting as a positive feedback to climate warming.