Why krill swarms are important to the global climate

Ocean life helps keep atmospheric levels of carbon dioxide lower by taking carbon out of the atmosphere and transporting it to the deep ocean, through sinking particles. Antarctic krill live in the Southern Ocean and gather in huge swarms. Importantly, they produce large, fast-sinking poo (called fecal strings), meaning that we get a rain of poo below these swarms, which takes carbon quickly to the deep ocean. We calculate how krill lower the amount of carbon in the atmosphere by estimating how many krill there are and how many fecal strings each produces. These calculations reveal that Antarctic krill living near sea ice remove 39 million tons of carbon from the surface ocean each year. That is about the same weight as 100 million polar bears! Krill are therefore not only important food for whales and penguins, but also vital engineers of our climate and so they require protection.