Abstract
The distribution and abundance of benthic foraminifera were studied along the coastal waters of Penang National Park, Malaysia, at four sites (Teluk Bahang, Teluk Aling, Teluk Ketapang, and Pantai Acheh) representative of varying levels of anthropogenic activities. A total of 144 sediment and water samples was collected and environmental parameters measured bimonthly between October 2010 September 2011 along four transects at 200-m intervals from the low-tide line to 1200 m offshore. Sediments were mostly muddy and contained substantial organic matter (typically >7%); waters were warm (similar to 30 degrees C) and somewhat brackish (similar to 29-30 parts per thousand). Specimens of the stress-tolerant genera Ammonia and Elphidium dominated assemblages along all transects. Cluster analysis separated the stations into four groups. The Group A1 stations (200 m offshore of Teluk Bahang and Teluk Aling) were characterized by the sandiest sediments, highest organic sediment concentrations (17%), a tendency for hypoxia [mean Ammonia-Elphidium Index (AEI) = 98], highest foraminiferal abundances (mean: 359 individuals/cm(3)), and relatively low diversities (mean H'=0.25). Group A2 included mostly Pantai Acheh stations, where mean concentration of organic matter (11%) and foraminiferal density (57 individuals/cm(3)) were lower than in Group A1 stations, diversity was slightly higher (H'=0.37), and the AEI was similar (97). Group B1 represented the most stations from 11 sites in Teluk Bahang, Teluk Aling, and Teluk Ketapang, and had the lowest mean organics (9.7%) and intermediate densities (42 individuals/cm(3)) and diversities (H'=0.45). Group B2 included only the Teluk Ketapang stations furthest from shore, with the lowest mean foraminiferal densities (7 individuals/cm(3)) and AEI (79) and the highest diversities (H'=0.56). The Teluk Ketapang site was also the least subject to anthropogenic stressors. The spatial distributions of foraminifera appeared to reflect the sedimentary environment and input of labile organic matter from anthropogenic sources.