Various ice shelves, including the Filchner-Ronne Ice Shelf, fringe the Weddell sea. Some of the ice shelves on the east side of the Antarctic Peninsula, which formerly covered roughly of the Weddell Sea, had completely disappeared by 2002. The Weddell Sea has been deemed by scientists to have the clearest water of any sea. Researchers from the Alfred Wegener Institute, on finding a Secchi disc visible at a depth of on , ascertained that the clarity corresponded to that of distilled water.