Why penguin poo can cause Antarctic ice to melt

Scientists have found that penguin poo, called guano, can cause Antarctic snow to melt at a faster than normal rate.

This happens because the poo provides nutrients that help a tiny type of single-cell plant, called snow algae, grow.

Snow algae is found all over Antarctica, but it behaves differently in different areas.

In areas of low nutrients, the snow algae produces a red colour and grows at a very slow rate.

But where there is high nutrients, like in areas where penguins and other sea birds live and poo, the pigment is green and can grow at a faster rate.

Snow containing green algae absorbs more solar energy and that means it melts more quickly.

The researchers from the University of Colorado collected snow samples from areas of Antarctica both near and away from penguin colonies.

They compared the amount and type of algae growing in the snow.

They discovered the green blooms caused faster rates of melting in the areas where marine nutrients were found - in the penguin waste.

The research, which was published in Journal of Geophysical Research: Biogeosciences, also showed that as the penguins walk their poo across new areas of snow it feeds the algae which in turn makes snow there more likely to melt too.

One of the lead authors of the study, Alia Khan, says this phenomenon has not yet been considered in predictions of melting ice and snow in Antarctica but is important in the future.

She predicts the penguins will continue to move closer to the South Pole due to rising temperatures, which will continue to spread this green snow algae further across the frozen continent.