Premium
Methane oxidation in contrasting soil types: responses to experimental warming with implication for landscape‐integrated CH 4 budget
Author(s) -
D'Imperio Ludovica,
Nielsen Cecilie Skov,
WestergaardNielsen Andreas,
Michelsen Anders,
Elberling Bo
Publication year - 2017
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.13400
Subject(s) - environmental science , growing season , sink (geography) , ecosystem , methane , wetland , atmospheric sciences , climate change , flux (metallurgy) , global warming , greenhouse gas , hydrology (agriculture) , agronomy , ecology , chemistry , geography , cartography , geotechnical engineering , organic chemistry , engineering , geology , biology
Arctic ecosystems are characterized by a wide range of soil moisture conditions and thermal regimes and contribute differently to the net methane ( CH 4 ) budget. Yet, it is unclear how climate change will affect the capacity of those systems to act as a net source or sink of CH 4 . Here, we present results of in situ CH 4 flux measurements made during the growing season 2014 on Disko Island (west Greenland) and quantify the contribution of contrasting soil and landscape types to the net CH 4 budget and responses to summer warming. We compared gas flux measurements from a bare soil and a dry heath, at ambient conditions and increased air temperature, using open‐top chambers ( OTC s). Throughout the growing season, bare soil consumed 0.22 ± 0.03 g CH 4 ‐C m −2 (8.1 ± 1.2 g CO 2 ‐eq m −2 ) at ambient conditions, while the dry heath consumed 0.10 ± 0.02 g CH 4 ‐C m −2 (3.9 ± 0.6 g CO 2 ‐eq m −2 ). These uptake rates were subsequently scaled to the entire study area of 0.15 km 2 , a landscape also consisting of wetlands with a seasonally integrated methane release of 0.10 ± 0.01 g CH 4 ‐C m −2 (3.7 ± 1.2 g CO 2 ‐eq m −2 ). The result was a net landscape sink of 12.71 kg CH 4 ‐C (0.48 tonne CO 2 ‐eq) during the growing season. A nonsignificant trend was noticed in seasonal CH 4 uptake rates with experimental warming, corresponding to a 2% reduction at the bare soil, and 33% increase at the dry heath. This was due to the indirect effect of OTC s on soil moisture, which exerted the main control on CH 4 fluxes. Overall, the net landscape sink of CH 4 tended to increase by 20% with OTC s. Bare and dry tundra ecosystems should be considered in the net CH 4 budget of the Arctic due to their potential role in counterbalancing CH 4 emissions from wetlands – not the least when taking the future climatic scenarios of the Arctic into account.