Penn Earth and Environmental Science Professor Finds Indications of Climate Change in Southern Ocean

To investigate the interplay between climate change and the ocean, Irina Marinov, an assistant professor in the Department of Earth and Environmental Science, has found it necessary to straddle disciplines.

Marinov, who studied physics as an undergraduate before earning her doctorate in atmosphere and ocean sciences, exemplifies an interdisciplinary approach. Her research into the Southern Ocean, the waters that encircle Antarctica, integrates analyses of the physics and chemistry of oceans and atmosphere with studies of the biological components that play a role in the global carbon cycle.

Though sometimes overlooked by scientists, the Southern Ocean below the 30th parallel takes up more than 60 percent of the anthropogenic heat produced on Earth and 40 to 50 percent of the anthropogenic carbon dioxide penetrating into the oceans. The Southern Ocean is emerging as very important for regulating climate.

Writing in Nature Climate Change earlier this year, Marinov and colleagues attempted to explain why the Antarctic Bottom Waters, the ocean’s deepest current, has been shrinking in recent decades. Because the current “hides” heat and carbon from the atmosphere, climate scientists have feared that its slow-down could have repercussions for global warming. These changes have occurred, Marinov explains, because increased precipitation around Antarctica—a consequence of climate change—has made the ocean surface waters fresher, and thus less dense. These lighter waters are less prone to move down through the water column and mix with deeper waters.