An Unexpected Discovery at the Air-Water Interface

Ocean acidification, mammal respiration, and aerosol formation all depend on chemistry that occurs at air-water interfaces. In new research, scientists from the Department of Energy's Lawrence Berkeley National Laboratory ÜBerkeley Lab) have discovered which pathway carbon dioxide (CO₂) molecules follow on their way from the atmosphere into water - and it's not the one that they expected. The oceans absorb roughly 30% of all anthropogenic CO₂ emissions. In water, the CO₂ forms carbonic acid, changing the marine environment in ways that are harmful to some sea life. In our bodies, air that crosses the wet membranes lining our nasal tracts influences the pH of our blood. But just how the local chemistry changes depends on how the dissolved CO₂ separates into two different ions with different charges - doubly charged carbonate and singly charged bicarbonate - near the liquid surface. Berkeley Lab researchers now show an enhanced concentration of carbonate at air-water interfaces, where they expected to find more bicarbonate.