Penguin droppings may be contributing to a surprising environmental problem in Antarctica, a new study has found. Published in the Journal of Geophysical Research: Biogeosciences, the research shows that nutrients from penguin guano help snow algae grow faster. As global warming continues, these algae are becoming more widespread across Antarctica and darkening the snow’s surface – which may speed up melting.

The colour of algae around the South Pole changes depending on the nutrients available. When algae lack nutrients, they turn red to protect themselves from sunlight; when nourished, they use chlorophyll – the green pigment that drives photosynthesis – to grow. As snow algae spread and darken the surface, the snow absorbs more sunlight, feeding a cycle linked to global warming that penguin droppings may accelerate.

A missing piece of the melt puzzle

The relationship between wildlife, nutrients and snow algae is an important missing part of projections about the expansion of ice-free areas in Antarctica, said senior author Alia Khan, a cryosphere biogeochemist. She explained that failing to account for these biological effects that darken snow could lead to an underestimation of how quickly coastal snowpacks are melting and how rapidly ice-free land is expanding across the continent. The findings arrive as Antarctica continues to lose ice amid changing environmental conditions: a study published in the journal Scientific Data last month found that Antarctica and Greenland have together lost about 12.5 trillion tons of ice over the past 47 years, with about 84 per cent of that loss attributed to glaciers flowing into the ocean faster than previously recorded, rather than surface melting.

Guano as a wildlife tracer

Penguin droppings have already proved scientifically useful in another way: tracking wildlife populations. In 2024, satellites spotted new colonies of Emperor penguins because large patches of their droppings were visible from space. The new study adds a further dimension – showing how even the waste of the continent’s most iconic animals is entangled with the physical processes reshaping the ice.