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Scientists Find Good News About Methane Bubbling Up From the Ocean Floor Near Santa Barbara

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  • mtneuman@juno.com
    Scientists Find Good News About Methane Bubbling Up From the Ocean Floor Near Santa Barbara Santa Barbara CA (SPX) Jan 03, 2008 Methane, a potent greenhouse
    Message 1 of 1 , Jan 2, 2008
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      Scientists Find Good News About Methane Bubbling Up From the Ocean Floor
      Near Santa Barbara

      Santa Barbara CA (SPX) Jan 03, 2008
      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.
      http://www.terradaily.com/reports/Scientists_Find_Good_News_About_Methane
      _Bubbling_Up_From_the_Ocean_Floor_Near_Santa_Barbara_999.html
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