At first whiff, this is a poop story. A penguin poop story.

A story about poop that smells so bad, Alia Khan, an associate professor of aerospace engineering at CU Boulder, struggles to find words to describe the odor that meets her when she steps off a small inflatable boat onto the western coast of Antarctica near penguin rookeries. 

But this is also a global climate change story with serious implications for those trying to predict where the planet is headed.

The samples that Khan and her team collected reveal that penguin poop is fertilizing algae growing on Antarctic snowfields, spreading a dark green blanket that causes snow and ice beneath to absorb more solar radiation and melt faster.  And there’s a ton of room for this algae to grow.  

“Current projections of Antarctic snowmelt and ice-free terrain expansion do not account for this,” Khan said. “This is a new part of the conversation.” 

The findings raise a serious question: Are scientists’ current models and predictions about climate change underestimating the rate of ice melt by not taking into account the impact of penguin poop?

Multiple colors of snow algae are visible near a penguin rookery in Antarctica. (Credit: Annette Bombosch)

“As penguin distributions shift poleward along the Antarctic Peninsula due to warming, the footprint of guano-fueled green snow blooms and accelerated ice melt will follow,” Khan said. 

The research, published Oct. 7, is a unique discovery about how flora and fauna interact in surprising ways in one of the most desolate and hard-to-reach places on Earth. 

For Khan, it’s also the start of unlocking a mystery that grabbed her attention about a decade ago when she saw a  photo of snow algae at an Antarctic science workshop.

“I was struck by how dark snow with algae was versus snow without it,” she said.

A smelly job

Antarctica doesn’t give up its secrets easily.

Just read the harrowing journals of the grizzled explorers who survived in 1915 when their ship, the “Endurance,” was locked in sea ice and eventually sank. The vessel now sits 10,000 feet under the sea off the continent’s coast. 

Ellie Ryan also knows how hard it is to escape the continent with all your belongings intact. 

As her boat rocked through the infamous Drake Passage, where massive winds and ocean currents circle Antarctica, the huge waves made it hard to keep her glassware full of penguin guano and algae samples from rolling off the table and shattering. 

“We were doing science not on our own terms,” said Ryan, a graduate student in environmental science at Western Washington University and the lead author of the study. “I’m used to working in a lab.” 

It wasn’t much easier on land, where the team spent multiple weeks scooping poop and algae into bottles.

Alia Khan collects samples of snow algae in Antartica. (Credit: Brendan Hodge)

“There’s tons of penguin poop. It’s on your boots. We try to squat or kneel on a tarp when we grab the samples,” Khan said. “And the penguins are super loud and smelly. They often wander right through where we’re sampling.”

The animals are easier to enjoy in the pictures, she quipped.

The scientists then spent multiple months processing the samples and counting the number of cells present under a microscope. They discovered the green pigments, which signal the algae is in reproduction mode, contained far more phosphate than the red pigments, which signal a more dormant stage of the algae.

Phosphate is a key ingredient in penguin guano, and the scientists found an association between that phosphate and the growing algae. 

“The neatest thing that has come out of this research has been thinking about entire ecosystem impacts,” Ryan said. “We have a pretty tiny organism off on its own doing its own thing, but there are a lot of external factors that can impact its growth and development.”

The bigger picture

Scientists have long known how different organisms interact in ecosystems like temperate rainforests. But researchers like Khan and Ryan are just starting to unlock such discoveries in Antarctica.

“This is a good example of how much we have to learn,” Ryan said. “Antarctica is often overlooked just because it’s so far away, and there’s not much life down there, but the poles are really important. And doing research down there is really important because of the shifting planet.”

Ellie Ryan collects snow algae samples in Antarctica. (Credit: Emi Neal)

Scientists still have work to do with the algae question. How long does the species live? How far will it spread, and how quickly?

Drones and time-lapse cameras will help the scientists start to get those answers on future trips.

“Antarctica plays a significant role in the global climate. It is the largest part of the global cryosphere, which serves as Earth’s mirror, reflecting incoming solar radiation back to space,” Khan said. “As the Antarctic snowpack darkens, it not only melts faster and reduces regional glacier mass, but it also exposes darker land underneath. This accelerates the ice-albedo feedback which triggers a positive loop of local warming and enhanced melt that ultimately drives global sea-level rise. This biogeochemical connection is new, and it’s not incorporated into any of the models yet.”