Monday, September 1, 2014

Climate Shocker: Warming Oceans Create Great Plumes of Methane Bubbles Near Atlantic Coast

From Alternet:  http://www.alternet.org/environment/warming-oceans-create-bubbles-methane-gas

The bubbles could add some 90 tons of greenhouse gases to the atmosphere.

Cliff Weathers August 27, 2014

Streams of methane bubbles are percolating along the Atlantic coast between North Carolina’s Outer Banks and Massachusetts’ Cape Cod.

According to the journal Nature, surges of bubbles are flowing from hundreds of ocean-floor leaks. Researchers say the plumes likely contain methane and could add as much as 90 tons of methane—a greenhouse gas much more potent than carbon dioxide — to the atmosphere each year. The methane bubbles may also hasten ocean acidification.

In the Geoscience newsletter published by Nature, researchers say that some two-thirds of the methane emissions come from methane-rich ices deep in the ocean that may be decomposing due to warming waters along the ocean floor. What effect these emissions will have on the atmosphere or the chemical makeup of the ocean is not immediately clear, but scientists are concerned. 

The bubbles first came into view on sonar scans of the ocean floor during oceanographic expeditions between 2011 and 2013. The expeditions ranged from Cape Hatteras in North Carolina to Georges Bank off Cape Cod and covered more than 36,000 square miles, an area about the size of Indiana. 
The scanned area includes the margin of the continental shelf and the sloping areas seaward and to the east.

Within a distance of about 590 miles, researchers found some 570 bubble plumes, which is considered to be an extraordinary amount. Previously, researchers studying the area had only detected an incidental number of bubble plumes. While some of the plumes extended far from the ocean floor, most of the bubbles dissolved into the water before they could reach the water’s surface.

The next step for the oceanographic researchers is to collect samples of the bubbles, says Carolyn Ruppel, a geophysicist at the U.S. Geological Survey at the Woods Hole, Massachusetts field center and a co-author of the study.

Continue reading at:  http://www.alternet.org/environment/warming-oceans-create-bubbles-methane-gas

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