1.4 Kilometer Plume Found Bubbling Up From Seafloor Off California Coast - Possible Methane Venting

An oceanographic survey has discovered a 1,400-meter-tall plume rising from the seafloor off the coast of California. Water samples taken at the site, about 32 kilometers northwest of Cape Mendocino, indicate that the feature isn’t mineral-rich water spewing from a hydrothermal vent, but researchers aren’t yet sure exactly what the feature is made of.

The mystery plume was first spotted on sonar in the dark hours of May 17, says James V. Gardner, a marine geologist at the University of New Hampshire in Durham. At the time, no one on the deck of the vessel that discovered the plume could see if it disturbed the sea surface, he and his colleagues report in the August 11 Eos. When the vessel returned to the site about two weeks later during daylight hours, scientists hovered over the spot and lowered sensors into the 1,800-meter-deep waters to take samples. During that hours-long visit, the sea looked normal — researchers saw no bubbles, unusually colored water or other signs of irregularities.

Gardner and his colleagues suggest that the plume is made up of a stream of methane bubbles coated with a veneer of methane-rich ice. That ice coating, a material called methane hydrate, is stable in deep water, where pressure is high and the water is cold. When the ice-cloaked bubbles ascend into warmer waters near the surface, the ice melts and the methane dissolves into the sea. In the coming months, further analyses of water samples taken from the plume may confirm the team’s conjecture.

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http://www.sciencenews.org/view/generic/id/46526/description/Bubblin%E2%80%99_plume

If it reaches the atmosphere, enhanced atmospheric GHGs.

Either way, handy for speeding up the next evolutionary go-round.

are acidic but methane itself is the weakest acid known.

The risk of methane is entirely tied to its GWP.

EDIT

The team found that most of the methane is being dissolved into the seawater and did not detect evidence of the gas breaking the surface of the ocean and getting into the atmosphere. They stress that this does not mean that the gas does not enter the atmosphere. They point out that the methane seeps are unpredictable and erratic in quantity, size and duration.

It is possible that larger seeps at different times and locations might in fact be vigorous enough to break through the ocean surface. Most of the methane reacts with the oxygen in the water to form carbon dioxide, another greenhouse gas. In sea water, this forms carbonic acid which adds to ocean acidification, with consequent problems for biodiversity.

Graham Westbrook, lead author and professor of geophysics at the University of Birmingham said: "If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane a year - equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean."

The team is planning another expedition next year to observe the behaviour of the methane plumes over time. They are also engaged in ongoing research into the amount of methane hydrate under this area of the ocean floor.

EDIT

http://news.bbc.co.uk/2/hi/science/nature/8205864.stm

It sounds like this methane hydrate is from a volcanic source.

Are there also basic materials being produced, neutralizing the overall pH in the area?

There's a lot of ultramafic materials being generated in the area. They're capable of producing some odd surface reactions, especially in the Franciscan shear zone.

But methane is not the acid, carbon dioxide is.

Interestingly a lot of what I am working on these days involves combustion under water at high pressures.

There are methane oxidizing microflora and microfauna by the way, well known.

:popcorn:

:cry:

That is all.