Abstract

The distribution and abundance of live (rose Bengal-stained) and dead infaunal foraminifera have been documented in short cores taken at four locations representing a narrow range of salinity settings in the mangrove swamps of the Setiu wetland, Terengganu, peninsular Malaysia. Cores were taken at mud-rich sites, two in the mid-swamp and two in the high swamp, from mainland-fringing mangrove swamps characterized by generally sandy substrates. Twenty-four taxa were recorded as live. Of these, two were restricted to the mid-swamp, eight were restricted to the high swamp, seven were restricted to shallow-infaunal depths (0–16 cm), and three were restricted to deep-infaunal depths (>16 cm). Thirteen taxa occurred both shallow and deep infaunally and 13 occurred at both high- and mid-swamp sites. Only six taxa, Ammobaculites exiguus, Bruneica clypea, Caronia exilis, Haplophragmoides wilberti, Siphotrochammina lobata, and Trochammina inflata were found live in all four cores.

The down-core patterns of foraminiferal data in high swamp core SET10 SET1, high-swamp core SET09 TR2 15A and mid-swamp core SET09 TR3 7A are not significantly impacted by deep-infaunal contribution, down-core taphonomic loss, or bioturbation. This suggests that all three cores could record sea-level changes. In contrast, mid-swamp core SET 09 TR1 7A exhibits significant enrichment of down-core assemblages by deep-infaunal foraminifera and extensive down-core taphonomic loss of tests, thus precluding its use for sea-level reconstructions.

It is arguable whether the basis for down-core sea-level reconstructions should be surface samples of transects across the mangrove swamp because an average of only 7% of the total number of live foraminifera in the four cores occurs in the 0–2 cm depth interval; most of the standing crop occurs in the 0–16 cm interval. However, because all abundant taxa occur both shallow (<16 cm) and deep (>16 cm) infaunally and assemblages in the 0–2 cm interval are very similar to those in the 0–16 cm interval, down-core sea-level reconstructions based on 0–2 cm surface samples, with a calculated error range of ca ±18 cm, could be attempted. Thus, it is possible that a sea-level signal could be preserved in foraminiferal assemblages from the mangrove swamps of Setiu, Malaysia, albeit with a relatively low resolution.

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