Distributed natural gas venting offshore along the Cascadia margin.

Riedel, Michael , Scherwath, Martin, Römer, M., Veloso, Mario, Heesemann, M. and Spence, G. D. (2018) Distributed natural gas venting offshore along the Cascadia margin. Open Access Nature Communications, 9 (3264). DOI 10.1038/s41467-018-05736-x.

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Supplementary data:

Abstract

Widespread gas venting along the Cascadia margin is investigated from acoustic water column data and reveals a nonuniform regional distribution of over 1100 mapped acoustic flares. The highest number of flares occurs on the shelf, and the highest flare density is seen around the nutrition-rich outflow of the Juan de Fuca Strait. We determine similar to 430 flow-rates at similar to 340 individual flare locations along the margin with instantaneous in situ values ranging from similar to 6 mL min(-1) to similar to 18 L min(-1). Applying a tidal-modulation model, a depth-dependent methane density, and extrapolating these results across the margin using two normalization techniques yields a combined average in situ flow-rate of similar to 88 x 10(6) kg y(-1). The average methane flux-rate for the Cascadia margin is thus estimated to similar to 0.9 g y(-1) m(-2). Combined uncertainties result in a range of these values between 4.5 and 1800% of the estimated mean values.

Document Type: Article
Keywords: METHANE HYDRATE DEPOSITS; NORTHERN CASCADIA; TEMPORAL VARIABILITY; MARINE-SEDIMENTS; VANCOUVER-ISLAND; SUBDUCTION ZONE; FLUID EXPULSION; BLACK-SEA; BUBBLES; OCEAN
Research affiliation: MARUM
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.1038/s41467-018-05736-x
ISSN: 2041-1723
Date Deposited: 31 Aug 2018 08:06
Last Modified: 24 May 2019 09:42
URI: http://oceanrep.geomar.de/id/eprint/44087

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