Undersea volcanic activity appears to provide a dampening influence on global warming as the seabed eruptions create nutrient-rich water that feeds carbon dioxide-eating plants.

Writing in the journal Nature Geoscience, Australian and French scientists show that hydrothermal vents around underwater volcanoes in the Southern Ocean spew iron.

After billowing to near the surface, the mineral allows single-cell organisms called phytoplankton to bloom, soaking up the greenhouse gas in the process. The world's oceans are thought to remove 20 percent to 25 percent of the atmospheric carbon dioxide produced by human activities.

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