A Cool Discovery: Penguin Poop Powers Cloud Formation in Antarctica

By Mary Leonard

Penguins aren’t just cute—these black and white birds, who live exclusively in the Southern Hemisphere, produce something very important to the Antarctic climate: poop.

More specifically, the ammonia in penguin guano is vital to cloud formation above Antarctica. Climate scientists are particularly interested in clouds over the South Pole, because the ice shelves and sea ice in this area are shrinking due to rising temperatures.

Sowing the Seeds of Clouds

One role of clouds is to help regulate surface temperatures. Clouds help control the amount of solar energy that reaches the surface of the Earth and keep the planet cooler by reflecting sunlight back into space.

Water is always present in the Earth’s atmosphere, but water molecules can’t condense into cloud droplets without surfaces to gather on. These surfaces are known as cloud condensation nuclei (CCN), and they are hygroscopic (water-attracting) particles on which cloud droplets can form. It turns out that the ammonia in penguin feces combines with other gases produced by marine phytoplankton to help create CCN in the Antarctic region. This contributes to new particle formation (NPF), a major contributor to CCN globally.

Observations at Marambio Station

Weather over the Southern Ocean and Antarctica has an impact on global climate. As a result, researchers are seeking to better understand how clouds form in this region. A team of scientists at Marambio Station near the northernmost tip of the Antarctic peninsula measured ammonia and other gases in the atmosphere from January 10 to March 20, 2023.

In most measurements, little or no ammonia was detected. However, when winds blew from the direction of a nearby Adélie penguin colony, the ammonia concentration jumped to 13.5 parts per billion, or 1,000 times higher than areas without penguins. Even though the levels of other gases, particularly dimethylamine, remained low, new particle formation rates increased as much as 10,000-fold.

On February 1, 2023, the scientists observed a particularly strong particle formation event involving ammonia. After six hours of rapid NPF and particle growth, fog began to form. The team continued collecting samples in the fog and observed increases in cloud droplet size, the sizes of ammonium sulfate particles in droplet residues, and the CCN concentration. This was direct evidence that NPF and particle growth promoted by ammonia directly contributed to CCN and cloud droplet formation.

Penguins Make a Lasting Contribution

The penguins left their breeding site in the middle of the study as part of their annual migration. However, the ammonia concentration in the wind blowing from the direction of the site remained highly elevated for more than a month after the penguins’ departure because the ground was covered in their excrement. Without penguin poop, cloud formation in the region wouldn’t be as strong, leading to higher temperatures and possibly faster melting of sea ice. And that’s how penguins, those chill critters, are doing their part to help keep the Earth cool.