The LDGO-Thorndike film recording nephelometer was used in three modes (profiling, short-term tethered and long-term moored) to measure changes in particle concentrations on time scales of minutes to weeks and space scales of meters to 25 km while measurements were being made on production and settling rates of particles. Although the nepheloid layer had no large near-bottom increase suggestive of local resuspension, there was an unusually thick nepheloid layer due to resuspension and advection of sediment from the basin walls. The concentration of particles increased by a factor of 3 between 900 m and the seafloor at 3840 m, while the vertical flux of particles measured in traps increased by only a factor of 1.7 over that distance. The horizontal flux of particles past traps at all depths is estimated to have varied by less than 20% and, therefore, does not appear to influence the flux measured with sediment traps. Changes with time in small-particle concentrations measured by the moored nephelometer were less than 30%, but the concentration of large particles changed by 100%.