Widespread Methane Leakage from the Seafloor on the Northern US Atlantic Margin

Metadata Updated: February 27, 2019

Methane emissions from the sea floor affect methane inputs into the atmosphere, ocean acidification and de-oxygenation, the distribution of chemosynthetic communities and energy resources. Global methane flux from seabed cold seeps has only been estimated for continental shelves, at 8 to 65 Tg CH4 yr−1, yet other parts of marine continental margins are also emitting methane. The US Atlantic margin has not been considered an area of widespread seepage, with only three methane seeps recognized seaward of the shelf break. However, massive upper-slope seepage related to gas hydrate degradation has been predicted for the southern part of this margin, even though this process has previously only been recognized in the Arctic. Here we use multibeam water-column backscatter data that cover 94,000 km2 of sea floor to identify about 570 gas plumes at water depths between 50 and 1,700 m between Cape Hatteras and Georges Bank on the northern US Atlantic passive margin. About 440 seeps originate at water depths that bracket the updip limit for methane hydrate stability. Contemporary upper-slope seepage there may be triggered by ongoing warming of intermediate waters, but authigenic carbonates observed imply that emissions have continued for more than 1,000 years at some seeps. Extrapolating the upper-slope seep density on this margin to the global passive margin system, we suggest that tens of thousands of seeps could be discoverable.

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Metadata Date 2014-09
Metadata Created Date September 26, 2015
Metadata Updated Date February 27, 2019
Reference Date(s) August 24, 2014 (publication)
Frequency Of Update notPlanned

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Harvested from NOAA CSW Harvest Source

Additional Metadata

Resource Type
Metadata Date 2014-09
Metadata Created Date September 26, 2015
Metadata Updated Date February 27, 2019
Reference Date(s) August 24, 2014 (publication)
Responsible Party (Principal Investigator)
Contact Email
Access Constraints Access Constraints: No access constraints. Use Constraints: No Use constraints.
Bbox East Long -66
Bbox North Lat 41
Bbox South Lat 32
Bbox West Long -77
Coupled Resource
Frequency Of Update notPlanned
Guid WidespreadMethaneLeakagePublication
Harvest Object Id e34a01d8-fba4-4c40-a9d6-fed6a37ba410
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2011-09-15
Temporal Extent End 2013-06-29

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