Electron microprobe analysis of suspended matter in the Angola Basin

Electron microprobe analysis of suspended-matter samples collected at diffe rent water depths at ten stations in the Angola Basin indicated that at eac h station, from top to bottom, the elementary composition of the suspended matter was very similar and differed from the composition of the suspended matter at the adjacent stations. This indicates that the downward settling of the suspended matter is much faster than the horizontal transport and mi xing by the currents. Assuming that the suspended matter settles in the for m of flocs, or is scavenged by settling flocs, the suspended matter can ind eed reach the bottom in a shorter period than needed for the currents to co ver the distance between adjacent stations. Comparison with sediment trap d ata from the literature shows that also lateral transports and/or deep wate r gyres have to be invoked to further increase residence times of suspended matter in the water column. (C) 1999 Elsevier Science B.V. All rights rese rved.