Subsurface and Infaunal Foraminifera of Kemaman-Chukai Mangrove Swamps, East Coast Peninsular Malaysia

Abstract

This study analysed the distribution and abundance of dead and live (Rose Bengal stained) infaunal foraminifera from three short cores taken at three locations in the mangrove swamps of Kemaman-Chukai, Terengganu, Malaysia. Eighteen agglutinated taxa were recorded in assemblages dominated by Arenoparrella mexicana, Haplophragmoides wilberti and Miliammina fusca; and of these, only two taxa were recorded as live. The distribution of subsurface and infaunal foraminifera varied from core to core, as did their depth of occurrence. Core 1 (seaward core) was dominated by sandy deposits, relatively high salinity (32 ppt), and extensive crab mounds, displayed very low numbers of dead foraminifera inconsistently throughout the core, while no infaunal foraminifera were observed, indicating intense bioturbation by mangrove crabs. In Core 2 (middle core), even though the numbers of live foraminifera decreased down-core, the number of dead or subsurface foraminifera were inconsistent, indicating taphonomic loss of the tests. Core 3 (landward core) however, displayed ideal foraminiferal distribution patterns required in the palaeo sea-level reconstruction (with less taphonomic loss and decreasing number of infaunal foraminifera downcore). Because of the similarity displayed in the foraminiferal assemblages in the 0–1 cm and 10–11 cm intervals, the surface sample (0–1 cm) should be an acceptable basis for down-core reconstructions in this study. Live (Rose Bengal stained) infaunal foraminifera, though observed at 40–41 cm depth, are not considered abundant enough to influence the dead assemblage in the subsurface sediment and its applicability for palaeoenvironmental and sea-level reconstructions. Therefore, it is possible for palaeo sea-level to be reconstructed based on foraminiferal assemblages preserved in the Kemaman-Chukai mangrove swamps.