THE PPS-3 TIME-SERIES SEDIMENT TRAP AND THE TRAP SAMPLE PROCESSING TECHNIQUES USED DURING THE ECOMARGE EXPERIMENT

The PPS 3, a versatile and reliable sediment trap with a 0.125 m2 collecting area, has been developed to collect and seal from ambient water six successive samples of settling particles at water depths down to 3500 m. High-quality plastics and corrosion-free metallic components were used to construct the trap. A microprocessor-controlled electronic timer/motor assembly controls the changing of sample receiving cups, at intervals of 1 h to 45 days. The sample recovery success rate of more than 60 individual trap deployments, in various experiments since 1985, is 93%. The PPS 3 was used during the French program ECOMARGE (ECOsystemes de MARGE continentale). The trap preparation and mooring techniques used during this experiment, as well as the laboratory sample processing procedure prior to analysis (i.e. removal of swimmer, subsampling), are presented in detail.