National Geographic announced Tuesday, World Ocean Day, that it would recognize a fifth ocean on its maps and globes. The Southern Ocean encompasses the icy waters surrounding Antarctica, and scientists say it is an oceanographically and ecologically unique region separate from the other four. The Southern Ocean is made up of what were previously known as the lowermost parts of the Atlantic, Pacific, and Indian Oceans. The publication, which has been making maps for more than a century, tweeted, “The swift current circling Antarctica keeps the waters there distinct and worthy of their own name: the Southern Ocean.” National Geographic’s leaders hope a specific designation will raise awareness of the need for conserving the region’s ecosystem, which faces threats from rising temperatures.