E/V Nautilus Mapping and ROV Dives Reveal Hundreds of Vents along the West Coast of the United States
Abstract
The Exploration Vessel (E/V) Nautilus has mapped more than 30,000 km2 of seafloor off the west coast of the United States between July 2015 and September 2016. The 30 kHz EM302 multibeam mapping system collects water column data in addition to bathymetry and backscatter. Examination of the water column data revealed hundreds of distinct vertical features, presumably plumes of methane gas released from the seafloor. While seafloor reservoirs of methane are thought to contribute 5-10% of the global discharge, inventories of seafloor methane seeps are poorly constrained due to the lack of data such as the distribution and abundance of seafloor gas plumes. The results of mapping efforts reveal an unexpected number of methane seeps. ROV dives were then used to provide geological context to the seeps and associated unique biological communities. Altogether these findings contribute significantly to our baseline inventory of seeps along the continental margins of the United States. The presence of unexpectedly large numbers of methane seeps on the US Pacific, Gulf and Atlantic margins may influence the management of human extraction activities on the margin seabed.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMOS41A1943K
- Keywords:
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- 9810 New fields (not classifiable under other headings);
- GENERAL OR MISCELLANEOUSDE: 3004 Gas and hydrate systems;
- MARINE GEOLOGY AND GEOPHYSICSDE: 3045 Seafloor morphology;
- geology;
- and geophysics;
- MARINE GEOLOGY AND GEOPHYSICSDE: 8010 Fractures and faults;
- STRUCTURAL GEOLOGY