Fig. 1.

As determined by video profiles, the relative number of particles (>500 μm) per frame, and the estimated particle number per liter (in brackets), in 100-m bins in a section across the equatorial Atlantic. White bars show the bottom depths (where bars are absent, depth exceeded 6,000 m). The euphotic zone was excluded from analysis (gaps in the top of the individual profiles), because daylight interfered with the contrast of the video images. RFZ indicates the extent of the Romanche Fracture Zone in the mid-Atlantic Ridge.