Nav: Home

Scientists find good news about methane bubbling up from the ocean floor

December 20, 2007

(Santa Barbara, Calif.) -- Methane, a potent greenhouse gas, is emitted in great quantities as bubbles from seeps on the ocean floor near Santa Barbara. About half of these bubbles dissolve into the ocean, but the fate of this dissolved methane remains uncertain. Researchers at the University of California, Santa Barbara have discovered that only one percent of this dissolved methane escapes into the air -- good news for the Earth's atmosphere.

Coal Oil Point (COP), one of the world's largest and best studied seep regions, is located along the northern margin of the Santa Barbara Channel. Thousands of seep fields exist in the ocean bottom around the world, according to David Valentine, associate professor of Earth Science at UC Santa Barbara. Valentine along with other members of UCSB's seeps group studied the plume of methane bubbles that flows from the seeps at COP.

Their results will soon be published as the cover story in Volume 34 of Geophysical Research Letters. This research effort is the first time that the gas that dissolves and moves away from COP, the plume, has been studied.

The amount of methane release from COP seeps is around two million cubic feet per day, according to Valentine. About 100 barrels of oil oozes out of this area as well. Methane warms the Earth 23 times more than carbon dioxide when averaged over a century. Thus the fate of the methane bubbles from the seeps is an important environmental question.

"We found that the ocean has an amazing capacity to take up methane that is released into it -- even when it is released into shallow water," said Valentine. "Huge amounts of gas are coming up here, creating a giant gas plume. Until now, no one had measured the gas that dissolves and moves away, the plume."

Valentine hypothesized that the methane is oxidized by microbial activity in the ocean, thus relieving the ocean of the methane "burden."

To arrive at this hypothesis, Valentine and lead author Susan Mau, a postdoctoral fellow in Valentine's lab, tracked the plume down current from the seeps at 79 surface stations in a 280 square kilometer study area. They found that the methane plume spread over 70 square kilometers.

By boat, the authors sampled the water on a monthly basis. They found variable methane concentrations that corresponded with changes in surface currents. They also found that more wind releases more methane into the atmosphere. Overall, they discovered that about one percent of the dissolved methane escapes into the atmosphere in the area they studied, a long-term average. This lead the authors to hypothesize that most of the methane is transported below the ocean's surface -- away from the seep area. Then it is oxidized by microbial activity.

To back up their findings of their surface sampling of the water, the scientists used a mass spectrometer hauled behind the boat as well. This equipment allowed for very high-resolution chemical information about the methane. This effort showed no significant difference in the numbers.

"We showed that the currents control the fate of the gas and supply it to bacteria in a way that allows them to destroy the methane," said Valentine.

Valentine said that while the seeps at COP are among the largest in the world, they can be found just about anywhere.
-end-


University of California - Santa Barbara

Related Methane Articles:

Microorganisms reduce methane release from the ocean
Bacteria in the Pacific Ocean remove large amounts of the greenhouse gas methane.
Origin of massive methane reservoir identified
New research provides evidence of the formation and abundance of abiotic methane -- methane formed by chemical reactions that don't involve organic matter -- on Earth and shows how the gases could have a similar origin on other planets and moons, even those no longer home to liquid water.
Methane not released by wind on Mars, experts find
New study rules out wind erosion as the source of methane gas on Mars and moves a step closer to answering the question of whether life exists on other planets.
Unexpected culprit -- wetlands as source of methane
Knowing how emissions are created can help reduce them.
Methane-consuming bacteria could be the future of fuel
Northwestern University researchers have found that the enzyme responsible for the methane-methanol conversion in methanotrophic bacteria catalyzes the reaction at a site that contains just one copper ion.
More Methane News and Methane Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...