This is Jim Fiorendino, your host for On the Ocean
Earth’s ocean and atmosphere form a complex interconnected system. With over 71% of Earth’s surface covered by water, the dynamics of the world’s oceans can have considerable impacts on atmospheric processes such as cloud formation. Studying cloud formation is important because clouds influence Earth’s heat budget and, consequently, Earth’s climate and weather. Clouds form when water condenses or ice crystals grow on aerosol particles in the atmosphere. The breaking of waves on the ocean entrains bubbles in the water, which rise and burst. Bubbles bursting and waves breaking launch water droplets containing organic material into the atmosphere, which dry out and form cloud condensation nuclei or ice nucleating particles. A diagram of this process is shown in Figure 1 below.
Dr. Daniel Thornton of the Texas A&M University Department of Oceanography is currently working with a team of scientists to understand the role of oceanic processes in cloud formation. Specifically, Dr. Thornton is studying the production of organic material in the oceans by phytoplankton.
Phytoplankton are microscopic photosynthetic organisms that form the base of oceanic food webs. They are known to form compounds that promote cloud formation, such as exopolymers. Exopolymers are large, irregularly-shaped molecules comprising roughly 10% of the organic matter in the ocean. This material leaks out of cells, particularly when they are eaten or die (Figure 2). Once in the ocean, this material may be carried to the surface by bubbles, where it is concentrated in a thin layer known as the sea surface microlayer. Wave activity can transfer this material to the atmosphere. Dr. Thornton hopes to link the biology of marine phytoplankton to the composition of organic matter in the ocean and the properties of marine organic aerosols in the atmosphere.
This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.
Contributing Professor – Dr. Daniel Thornton