The estimating the settling velocity of suspended organic matter (SOM) under the effects of salinity is necessary for developing a pelagic-benthic coupled ecosystem model to evaluate the coastal environment, where SOM is deposited on the sea bottom. In this study, laboratory experiments were performed with several materials, such as bentonite and SOM by using a particle distribution analyzer in order to estimate the settling velocity of SOM. From the experiment results, it was found that salinity accelerated the flocculation of settling particles, especially, loose flocs formed when SOM was consisted low amount of organic matter. As the flocked particle size increased, the settling velocity of SOM decreased.
