The mesopelagic zone is the chilly, dimly lit layer of ocean found 200-1,000 meters (660-3,300 feet) below the surface, which scientists say plays key roles in the marine food web and carbon cycle. On Oct. 15, delegates to the IUCN World Conservation Congress in Abu Dhabi adopted a motion to protect it. The motion calls for any activities that could harm the mesopelagic ecosystem, including fishing, geoengineering and deep-sea mining, to be approached with caution and guided by the best available science.