Antarctic krill (Euphausia superba) do much more than fill whales' bellies. These tiny crustaceans also play a huge role in Earth's carbon cycle.

They sequester around 40 million tonnes of carbon each year, mostly in their poo — that's the equivalent of taking 35 million cars off the road.

Yet there's plenty we don't know about these thumb-sized critters.

Now a new study has revealed what they get up to under the Antarctic winter sea ice, and how this behaviour affects carbon calculations.

Dive into the secret life of krill on Lab Notes, the show that brings you the science of new discoveries and current events.Get in touch with us: [email protected]