© Oregon State University
Large carbonate platform with intense bubble streams pouring out of the seafloor from under the carbonate cap.
Large carbonate platform with intense bubble streams pouring out of the seafloor from under the carbonate cap.
And what they have found is eye-opening. Since the first evidence of underwater methane was discovered in the late 1980s, only about 100 "seep sites" had been identified along the Northwest coast through 2015. They often were discovered by accident, when fishermen would spot anomalies on their fish-finders that turned out to be acoustic reflections of the bubbling methane gas.
But over the past two years the scientists-aided by new sonar technology on the Exploration Vessel (E/V) Nautilus, owned and operated by the Ocean Exploration Trust-have purposefully gone seeking evidence of underwater methane and have expanded the total number of offshore seep emission sites to a whopping 1,000 locations.
It is not yet clear whether the methane presents an opportunity for a new source of energy or a potentially serious environmental threat, but for now the researchers want to map the distribution of the sites and conduct research on the composition and sources of the gas. They believe they will discover new methane seeps this summer when they utilize several research vessels to conduct additional mapping off the Northwest coast.
Comment: In recent times hundreds of methane plumes have been discovered erupting along the US Atlantic coast, as well as for the first time in deep Arctic Ocean areas.
It is likely this increased methane outgassing and undersea volcanic activity (it is estimated there are up to one million of these 'submarine volcanoes') are contributory factors to the devastating huge ocean 'dead zones' which have quadrupled around the world since 1950, including in Atlantic open waters for the first time.
The significant increase of fish die offs and strange migratory behaviour of marine life could be considered other potential signs of such activity.