Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier
Autor: | Nick Ostle, Hugh Tuffen, Fiona S. Tweed, Philip A. Barker, Andrew W. Stott, Zheng Zhou, Aaron Chesler, Niall P. McNamara, Rebecca Kate Burns, Simon Oakley, Peter M. Wynn, Micha Stuart |
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Jazyk: | angličtina |
Rok vydání: | 2018 |
Předmět: |
010504 meteorology & atmospheric sciences
Earth science Climate Iceland lcsh:Medicine 010502 geochemistry & geophysics 01 natural sciences Methane Article Atmospheric Sciences Atmosphere chemistry.chemical_compound Ice Cover Glacial period Meltwater lcsh:Science Geothermal gradient 0105 earth and related environmental sciences geography Carbon Isotopes Multidisciplinary geography.geographical_feature_category lcsh:R Glacier chemistry Greenhouse gas Environmental science lcsh:Q Seasons Ice sheet Environmental Monitoring |
Zdroj: | Scientific Reports, Vol 8, Iss 1, Pp 1-8 (2018) Scientific Reports |
ISSN: | 2045-2322 |
Popis: | 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. |
Databáze: | OpenAIRE |
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