Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992-2009; sources and atmospheric flux.

Lorenson, Thomas D., Greinert, Jens and Coffin, Richard B. (2016) Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992-2009; sources and atmospheric flux. Limnology and Oceanography, 61 (S1). S300-S323. DOI 10.1002/lno.10457.

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Abstract

Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of the Arctic Ocean during 11 surveys spanning the years of 1992–1995 and 2009. During ice-free periods, methane flux from the Beaufort shelf varies from 0.14 mg CH4 m−2 d−1 to 0.43 mg CH4 m−2 d−1. Maximum fluxes from localized areas of high methane concentration are up to 1.52 mg CH4 m−2 d−1. Seasonal buildup of methane under ice can produce short-term fluxes of methane from the Beaufort shelf that varies from 0.28 mg CH4 m−2 d−1 to 1.01 mg CH4 m−2 d−1. Scaled-up estimates of minimum methane flux from the Beaufort Sea and pan-Arctic shelf for both ice-free and ice-covered periods range from 0.02 Tg CH4 yr−1 and 0.30 Tg CH4 yr−1, respectively to maximum fluxes of 0.18 Tg CH4 yr−1 and 2.2 Tg CH4 yr−1, respectively. A methane flux of 0.36 Tg CH4 yr−1 from the deep Arctic Ocean was estimated using data from 1993 to 1994. The flux can be as much as 2.35 Tg CH4 yr−1 estimated from maximum methane concentrations and wind speeds of 12 m/s, representing only 0.42% of the annual atmospheric methane budget of ∼ 560 Tg CH4 yr−1. There were no significant changes in methane fluxes during the time period of this study. Microbial methane sources predominate with minor influxes from thermogenic methane offshore Prudhoe Bay and the Mackenzie River delta and may include methane from gas hydrate. Methane oxidation is locally important on the shelf and is a methane sink in the deep Arctic Ocean.

Document Type: Article
Additional Information: WOS:000388560900022
Keywords: Dissolved methane, Beaufort Sea, Arctic Ocean
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems > DeepSea Monitoring
Kiel University
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/lno.10457
ISSN: 0024-3590
Contribution Number:
ProjectNumber
DSM22
Date Deposited: 12 Dec 2016 09:24
Last Modified: 23 Sep 2019 20:25
URI: http://oceanrep.geomar.de/id/eprint/35163

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