During its first dive of the cruise, the remotely operated vehicle Jason moved along and just above the border between the brownish normal seafloor (on the left) and murky black water that appeared to be the Deep Hypersaline Anoxic Basin (on the right). The white strip between them appeared to be where the halocline, or transition zone between normal seawater and hypersaline water, meets the seafloor. During Wednesday’s dive, the scientists found that the dark water is probably the halocline. They don’t know yet what the white strip is. The structure at the left edge of the frame is one of Jason’s manipulator arms. The items at the bottom of the frame are sediment samplers.