In the Southern Ocean, the world’s largest current in terms of volume transport — the Antarctic Circumpolar Current (ACC) — encircles Antarctica and connects the Atlantic, Indian and Pacific ocean basins, as it flows from west to east. The ACC influences ocean circulation and global climate, as it rises from the deep to interact with the atmosphere. In a new study, published in the Journal of Geophysical Research: Oceans, researchers have directly measured how seafloor topography affects the current’s structure — something that had only been theorized previously.