Methane bubbles from ocean floor wont make global warming worse

December 21st, 2007 - 5:58 pm ICT by admin  

Washington, Dec 21 (ANI): Researchers have discovered that only one percent of methane bubbles from the oceans floor escape into thin air, which makes it a good news for the Earth’s atmosphere, as the released gas wont make global warming worse.

Methane is a potent greenhouse gas, which warms the Earth 23 times more than carbon dioxide. It 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.

Thus, the fate of the methane bubbles from the seeps is an important environmental question.

In a study, led by Susan Mau, a postdoctoral fellow in David Valentine, associate professor of Earth Science at UC Santa Barbaras lab, the plume of methane bubbles that flows from the seeps at Coal Oil Point (COP) was studied.

Coal Oil Point (COP) is one of the world’s largest and best-studied seep regions, and it is located along the northern margin of the Santa Barbara Channel.

“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, he added.

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

Fro reaching the conclusion, the researchers tracked the plume down current from the seeps at 79 surface stations in a 280 square kilometre study area.

They found that the methane plume spread over 70 square kilometres.

The authors sampled the water on a monthly basis and found variable methane concentrations that corresponded with changes in surface currents. Also they found that more wind releases more methane into the atmosphere.

As a whole, they discovered that about one percent of the dissolved methane escapes into the atmosphere in the area.

The finding led 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.

“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.

The study will appear in Geophysical Research Letters. (ANI)

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