Temporal variability of amino acid, hexosamine, and carbohydrate fluxes onthe eastern Brazilian continental margin related to discharge of the Sao Francisco River, Brazil

Settling particles collected at 1550 m water depth off the Sao Francisco Ri ver, Brazil, between January and May 1995 showed peak fluxes of amino acids , hexosamines, and carbohydrates, which formed the onset of a three-week pe riod of high organic matter (OM) flux, coinciding with the high discharge p eriod of the river. Two phases of OM deposition exist: (1) the fluvial inpu t of nutrients triggering a bloom of non biomineralizing plankton, and (2) suspended sediment mainly derived from shelf erosion increasing the fluxes of refractory OM. This indicates the importance of seasonally varying hydro dynamic conditions and nutrient input from the continent for the production and sedimentation of OM to the continental margin of eastern Brazil.