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SUMMARY:Isotopic constraints on atmospheric methane sources - Dr Rebecca F
 isher\, Royal Holloway University of London
DTSTART:20110221T141500Z
DTEND:20110221T151500Z
UID:TALK28105@talks.cam.ac.uk
CONTACT:Dr Alex Archibald
DESCRIPTION:Carbon isotopic studies of atmospheric methane can provide con
 straints on the proportion of methane emitted to the atmosphere from diffe
 rent sources. At Royal Holloway δ13C in atmospheric methane is measured i
 n samples from a network of sites in the Arctic\, Atlantic and from Egham\
 , SW of London.\n\nThe carbon isotopic signature of some major Arctic and 
 sub-Arctic methane sources has been characterised from field studies. Meth
 ane from different sources has markedly different δ13C. Methane from nort
 hern wetlands has δ13C around -70‰\; Siberian natural gas is around -50
 ‰ and forest fire emissions are around around -28‰. Thus δ13C readily
  identifies specific source increments. The carbon isotopic signature of t
 he bulk methane increment in ambient Arctic air has also been measured in 
 air samples collected at the Zeppelin station\, Spitsbergen. Results indic
 ate a primarily biogenic source of methane to the Arctic in the summer mon
 ths\, most likely with a large wetland contribution.\n
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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