Typhoons bury tons of carbon in the oceans

Science Daily: A single typhoon in Taiwan buries as much carbon in the ocean -- in the form of sediment -- as all the other rains in that country all year long combined. That's the finding of an Ohio State University study published in a recent issue of the journal Geology.

The study -- the first ever to examine the chemistry of stream water and sediments that were being washed out to sea while a typhoon was happening at full force -- will help scientists develop better models of global climate change.

Anne Carey, associate professor of earth sciences at Ohio State, said that she and her colleagues have braved two typhoons since starting the project in 2004. The Geology paper details their findings from a study of Taiwan's Choshui River during Typhoon Mindulle in July of that year. Carey's team analyzes water and river sediments from around the world in order to measure how much carbon is pulled from the atmosphere as mountains weather away.

They study two types of weathering: physical and chemical. Physical weathering happens when organic matter containing carbon adheres to soil that is washed into the ocean and buried. Chemical weathering happens when silicate rock on the mountainside is exposed to carbon dioxide and water, and the rock disintegrates. The carbon washes out to sea, where it eventually forms calcium carbonate and gets deposited on the ocean floor.

If the carbon gets buried in the ocean, Carey explained, it eventually becomes part of sedimentary rock, and doesn't return to the atmosphere for hundreds of millions of years. Though the carbon buried in the ocean by storms won't solve global warming, knowing how much carbon is buried offshore of mountainous islands such as Taiwan could help scientists make better estimates of how much carbon is in the atmosphere -- and help them decipher its effect on global climate change….

A flood in Taiwan (on the Zhongshan North Road). Photo by Rico Shen, Wikimedia Commons, under the terms of the GNU Free Documentation license, Version 1.2