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Professor's research on sea bubbles
heats up study of global warming

Tiny bubbles in the ocean may not seem important, but they actually play a major role in controlling the world's climate.

Edward C. Monahan, director of the Connecticut Sea Grant College Program and professor of marine sciences, has been studying sea bubbles for 30 years. A physical oceanographer, he is internationally known for his scientific research on the role of breaking waves and bubbles in the exchange of gases and other material between the ocean and the atmosphere.

"When you have a soda, it tingles your nose because little bubbles burst and the little specks of water go up your nose," he explains. "Comparable microscopic bubbles form in the ocean. But the tiny particles of sea spray, marine aerosols which result when these oceanic bubbles burst, affect the heat balance of the earth and are important factors in climate and global change."

A breaking wave forms a whitecap and a column of bubbles submerged beneath it. This process creates a vent through which gas - such as carbon dioxide - that is dissolved in the ocean can escape into the atmosphere or through which gas in the atmosphere can become dissolved into the ocean. Clusters of bubbles on the surface make it easier for gases to dissolve or escape.

"The salt water drops are so small and light that they get pushed around by wind and are carried into the atmosphere, where they play a major role in cloud formation over the ocean," Monahan says.

Monahan and his current collaborators have taken the lead in developing algorithms that will make it possible to estimate global air-sea gas transfer rates from satellite measurements of oceanic whitecap coverage. The studies of sea-air exchange are critical because the amount of carbon dioxide - the significant gas in global warming - in the atmosphere is increasing, yet at a slower rate than we might expect given human activity, he says.

"With the burning of forests, coal and gas, we have been releasing a lot of carbon dioxide into the atmosphere increasingly every year for the past century," he says. "The ocean acts like a sponge, soaking up some of the excess carbon dioxide in the air. Our presumption is that the missing carbon dioxide is in the ocean."

As global warming increases, however, the ocean's ability to absorb carbon dioxide will decrease. Studies have shown that global warming will be greater in higher latitudes, and this will lessen the winds. Wave breaking, which is very wind dependent, would then occur at a slower rate. The future consequences of this could be disastrous, Monahan says, because the sea surface would become less friendly to gas transfer and the ocean wouldn't be able to take up carbon dioxide from the atmosphere at the current rate. An increasing amount of carbon dioxide would concentrate in the atmosphere, creating a more rapid global warming process and continuing a vicious cycle.

Monahan's research is funded by grants from the Office of Naval Research and the National Science Foundation.

Monahan, of Gales Ferry, who was elected an American Meteorological Society fellow this year, has been director of Sea Grant and a professor at UConn since 1986. He also oversees the Sea Surface Physics and Chemistry Laboratory at the Avery Point campus.

He earned his bachelor's degree in engineering physics from Cornell in 1959, his master's degree in physics at the University of Texas at Austin in 1961, his Ph.D. in oceanography from the Massachusetts Institute of Technology in 1966, and a senior doctorate from the National University of Ireland in 1984. His studies have been documented in more than 250 peer-reviewed journal articles and in scientific publications. He also is a fellow of the Royal Meteorological Society.

Renu Sehgal-Aldrich