Antarctic krill—and more importantly, krill poop—are an important part of the global climate system. Unlike many species that migrate miles across the surface, krill migrate vertically, depositing their carbon-filled waste deep below the surface. This helps mitigate climate change, but they’re under threat from capture for use as fishmeal to feed aquaculture operations or oils to manufacture nutraceuticals. Understanding their role in the twilight zone ecosystem is critical if we hope to avoid damaging this important function. Video by Pew Foundation.