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Arctic methane sources: Isotopic evidence for atmospheric inputs
Author(s) -
Fisher R. E.,
Sriskantharajah S.,
Lowry D.,
Lanoisellé M.,
Fowler C. M. R.,
James R. H.,
Hermansen O.,
Lund Myhre C.,
Stohl A.,
Greinert J.,
NisbetJones P. B. R.,
Mienert J.,
Nisbet E. G.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl049319
Subject(s) - methane , atmospheric methane , arctic , environmental science , methane emissions , the arctic , atmospheric sciences , climatology , geology , greenhouse gas , oceanography , chemistry , organic chemistry
By comparison of the methane mixing ratio and the carbon isotope ratio ( δ 13 C CH4 ) in Arctic air with regional background, the incremental input of CH 4 in an air parcel and the source δ 13 C CH4 signature can be determined. Using this technique the bulk Arctic CH 4 source signature of air arriving at Spitsbergen in late summer 2008 and 2009 was found to be −68‰, indicative of the dominance of a biogenic CH 4 source. This is close to the source signature of CH 4 emissions from boreal wetlands. In spring, when wetland was frozen, the CH 4 source signature was more enriched in 13 C at −53 ± 6‰ with air mass back trajectories indicating a large influence from gas field emissions in the Ob River region. Emissions of CH 4 to the water column from the seabed on the Spitsbergen continental slope are occurring but none has yet been detected reaching the atmosphere. The measurements illustrate the significance of wetland emissions. Potentially, these may respond quickly and powerfully to meteorological variations and to sustained climate warming.