STEM Today: Plankton in the Southern Ocean Adds Light to Cloudy Skies

A new study on the Southern Ocean demonstrates the importance of even the tiniest life forms in maintaining natural balance.

The study, published in the journal Science Advances, focuses on how microbes in the ocean can alter cloud activity. The connection between plankton— best known as the primary food source of larger marine animals such as whales— and clouds might not seem obvious, but researchers were already aware of a link between them. When plankton are tossed by waves or wind from the ocean, they collect condensation that helps to form clouds. By drawing CO2 down to earth through photosynthesis, plankton also assist in regulating the temperature of the planet.

Researchers from the University of Washington and the Pacific Northwest National Laboratory were particularly interested in why the Southern Ocean appears much brighter in the summer months. Although the connection between plankton and cloud formation was already known, it didn’t answer the question of why the light intensified in summertime. During summer, calmer seas contribute less spray that can then be turned into the aerosol particles that form clouds.

Using NASA satellite data, they were able to determine a possible reason for the increased sunlight during the summer months: the plankton forms a surface “scum” in the summer that is caught by the wind and drawn into the sky, creating more opportunities for condensation to form around the floating particles. Study co-author Daniel McCoy estimates that, “In the summer, we get about double the concentration of cloud droplets as we would if it were a biologically dead ocean.”

“We have really poor observations of everything in the Southern Ocean, and it’s a really important region,” said Robert Wood, a University of Washington professor of atmospheric sciences in a statement. “It also provides a glimpse of how a pristine, pre-industrial area might behave.”


Activity: To see how condensation works, take a glass cup and fill it with ice. Add room temperature water until the cup is nearly full. Now try the same procedure on a cup without any ice. Does more condensation form on the outside of one of the glasses? If so, why do you believe that is?

Jobs: Marine biologist, atmospheric scientist

Sources: Christian Science Monitor, Gizmodo

Photo credit: Creative Commons

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