Oceans have little impact on climate changes: experts

Climate experts have relied on the oceans to absorb enough of the greenhouse gas carbon dioxide to slow global warming, but new research by an international team of scientists shows that the oceans may have little impact on changes in the atmospheric climate.
The research, funded by the National Science Foundation, is the result of two international expeditions to the Pacific Ocean and is reported in the April 27 issue of the journal 'Science', published by the American Association for the Advancement of Science, disclosed sources here on Thursday.
The research indicates that instead of sinking, carbon dioxide is often consumed by animals and bacteria and recycled in the 'twilight zone', a dimly lit area 100 to 1,000 meters below the surface. Because the carbon often never reaches the deep ocean, where it could be stored and prevented from re-entering the atmosphere as a green-house gas, the oceans may not be able to perform the crucial role in greenhouse gas absorption and storage that has been assumed.
The researchers found that the twilight zone acts as a 'gate' that allows more sinking particles through, in some regions and fewer in others, complicating scientists' ability to predict the oceanic role in offsetting the impacts of greenhouse gases. These sinking particles, often called 'marine snow', supply food to organisms deeper down, including bacteria that decompose the particles. In the process, carbon is converted back into dissolved organic and inorganic forms that are re-circulated and reused in the twilight zone and that can make their way to the surface and back into the atmosphere.
The problem, say scientists, is that particles sink slowly, perhaps 10 to a few hundred meters per day, but they are swept sideways by ocean currents travelling many thousands of meters per day. To collect sinking particles, oceanographers use cones or tubes that hang beneath buoys or float up from sea floor.
Using new technology, the researchers found that only 20 percent of the total carbon in the ocean surface made it through the twilight zone off Hawaii, while 50 percent did in the north-west Pacific near Japan.