Scientists have discovered a surprising—and smelly—source of clouds in Antarctica: penguin poop.
According to a new study published in Communications Earth & Environment, ammonia gas emanating from these flightless birds’ guano sets off a chain of chemical reactions that causes clouds to form. These clouds may be changing local temperatures in the Antarctic—and perhaps the global climate.
At the Marambio Base on the Antarctic Peninsula, researchers led by Matthew Boyer—a doctoral candidate at the University of Helsinki in Finland—measured the concentration of ammonia wafting from a colony of 60,000 Aldelie penguins from January to March 2023.
When the wind blew from the direction of the colony, ammonia levels spiked, sometimes reaching 1,000 times above normal levels. In February, the penguins left the area to continue their annual migration, but the guano they left behind kept ammonia levels up to 100 times higher than normal for over a month.
Because penguins mainly eat fish and krill, their excrement is full of nitrogen waste that ultimately breaks down into ammonia. This chemical compound rises into the air as gas, then mixes with sulfur gas produced by marine microorganisms, such as phytoplankton. That reaction creates aerosol particles, which then join with water droplets to form clouds.
Previous studies have modeled this chain reaction before, but Boyer and his colleagues watched the clouds form in real time. In February 2023, they measured a particularly strong burst of aerosols from the guano, then sampled a fog that formed just a few hours later. This confirmed that the fog contained particles created by the reaction between ammonia from the guano and sulfuric acid from plankton.
“There is a deep connection between these ecosystem processes, between penguins and phytoplankton at the ocean surface,” Boyer told Grist. “Their gas is all interacting to form these particles and clouds.”
There are about 20 million penguins living in Antarctica, according to the British Antarctic Survey. This teeming population produces a lot of poop, and therefore a lot of clouds. Computer models have found that these clouds reflect sunlight, leading to significant ground cooling.
Boyer and his colleagues state that more research is needed to fully understand the clouds’ impact on local temperatures. But if they do have a cooling effect, they suggest that declining penguin populations could exacerbate Antarctic warming during the summertime.
“It is already understood that widespread loss of sea ice extent threatens the habitat, food sources, and breeding behavior of most penguin species that inhabit Antarctica,” the authors state. “Consequently, some Antarctic penguin populations are already declining, and some species could be nearly extinct by the end of the 21st century.”
Among the world’s 18 penguin species, 11 are globally threatened, according to BirdLife International. The Adelie penguins that Boyer studied, however, are one of the few species whose Antarctic population is experiencing an increase in numbers.
But if these poo clouds are less reflective than the ice beneath it, they may trap heat close to Earth’s surface and cause temperatures to rise, Boyer told the Washington Post. Getting to the bottom of these impacts is important because local changes in Antarctica and the Arctic can affect the whole world, particularly in terms of sea level rise.
“The oceans and the penguins are influencing the atmosphere and actually influencing the local climate in Antarctica,” Boyer told the Washington Post. “The local changes in Antarctica will have an impact on global climate.”
