4. Discussion
The means of the sedimentation rates of 29.49–59.53 mg cm−2 d−1 found in the present study are relatively high (Rogers, 1990 and Lane, 1991). The coral communities in this study had accumulated tremendous loads of sediment to the extent that dead corals were found to have mud draped on them. Therefore sediment deposition is considered as a chronic disturbance to coral reefs at Samui Island (Connell et al., 1997). It has caused a decrease of filter feeders and grazers, especially Diadema setosum ( Dikou and van Woesik, 2006 and Yeemin et al., 2009).