Statistical Characterisation of tropical seagrass bed sediment and adjacent unvegetated sediment in Lae-Lae Island of Makassar (Indonesia)

Abstract

The statistical characteristic of sediment is useful in interpretation of the past or future processes acting on the sediments. This paper reports the statistical characteristic of small island sediment taken from seagrass bed and adjacent unvegetated area. Surface sediment samples were collected from four sites using a sediment corer (PVC pipe with a diameter of 6 cm and a length of 15 cm) and dry sieved in the laboratory to determine grain size distribution. The grain size measurement in mm were converted into the phi (§) unit before calculating the statistical parameters of the sediment including mean grain size, sorting, skewness, and kurtosis using a GRADISTAT (a grain size distribution and statistics package for the analysis of unconsolidated sediments). The results show that both seagrass bed sediments and adjacent unvegetated sediments in the study site are characterized by medium to coarse-grained sand fractions, mostly poorly sorted, symmetrical to very coarse skewed, and have platykurtic, mesokurtic, and leptokurtic kurtosis. These findings highlight the practical use of grain size analysis to classify sedimentary environments and elucidate transport dynamics in the Lae-Lae Island.