Down-Core Variations of Foraminiferal Distribution in The Mangrove Sediments of Kapar and Matang, West Coast of Peninsular Malaysia

Abstract : The foraminiferal distribution in two mangrove core sediment samples collected from contrasting environments i.e., one from coastal plain (Kapar) and other from estuarine plain (Matang), was investigated. Altogether, 29 species represented by 12 families and 21 genera were encountered. At Kapar where salinity and pH are presumably high (sandy loam soil), the marine/ calcareous forams (655 ± 826 ind cm-3, mean ± 1SD) dominated the population, while Matang sediment was represented by agglutinated forams (94 ±115 ind cm-3) characteristic of brackish- water, and distributed under low salinity and pH regimes (silty loam with peat). The foraminiferal diversity indices are low for both Kapar (mean d 0.7, H 0.8 and J 0.5) and Matang (mean d 0.6, H 0.9 and J 0.8), albeit the population was rich in Kapar (404 ± 654 ind cm-3). On the basis of routines (e.g. BVSTEP, SIMPER) implemented in PRIMER (Plymouth Routines in Multivariate Ecological Research, UK), it was possible to demonstrate that species such as Ammonia beccarii, Arenoparrella mexicana, Elphidium discoidale and Haplophragmoides wilberti played a key role in discriminating the foraminiferal species associations (groupings) at Kapar and Matang. The faunal abundance (root-transformed data) indicated 7 groupings (Bray-Curtis similarity: 44%) in the down-core samples. While Groups 1-5 represented the combination of species found exclusively in Kapar, Groups 6-7 were characteristic of Matang environment. In summary, the fauna at Kapar implies brackish intertidal environment with hyperhaline condition (salinity: 25-30 psu and pH: 7-8), where Ammonia beccarii (375 ± 620 ind cm-3) and Elphidium discoidale (68 ±118 ind cm-3) outnumbered all others; Matang species indicated an estuarine upper to uppermost intertidal environment (salinity: 18-26 psu and pH: 6-7) dominated by Haplophragmoides wilberti (44 ± 63 ind cm-3) and Arenoparrella mexicana (25 ± 30 ind cm-3). Species distribution throughout the core sample (surface to bottom) collected from Kapar also signifies an active rate of sedimentation process close to river (Kapar Besar) mouth than the estuarine plain.