Accepted author manuscript, 1.16 MB, PDF document
Available under license: CC BY: Creative Commons Attribution 4.0 International License
Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier
AU - Burns, Rebecca Kate
AU - Wynn, Peter Michael
AU - Barker, Philip Anthony
AU - McNamara, Niall
AU - Oakley, Simon
AU - Ostle, Nicholas John
AU - Stott, Andy
AU - Tuffen, Hugh
AU - Zhou, Zheng
AU - Tweed, Fiona
AU - Chesler, Aaron
AU - Stuart, Micha
PY - 2018/11/20
Y1 - 2018/11/20
N2 - The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable ‘cap’ of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m-2 day-1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m-2 day-1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (-60.2 ‰ to -7.6 ‰ for δ13CCH4 and -324.3 ‰ to +161.1 ‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere.
AB - The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable ‘cap’ of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m-2 day-1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m-2 day-1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (-60.2 ‰ to -7.6 ‰ for δ13CCH4 and -324.3 ‰ to +161.1 ‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere.
U2 - 10.1038/s41598-018-35253-2
DO - 10.1038/s41598-018-35253-2
M3 - Journal article
VL - 8
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
M1 - 17118
ER -