BENTHIC FORAMINIFERAL DISTRIBUTIONS AS BIOINDICATORS IN COASTAL WATERS OF PENANG NATIONAL PARK, MALAYSIA FATIN I. MINHAT 1,4 ,KHAIRUN YAHYA 2 ,ANITA TALIB 3 AND OMAR AHMAD 1 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 (,30uC) and somewhat brackish (,29–30%). 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 H9= 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 (H9= 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 (H9= 0.45). Group B2 included only the Teluk Ketapang stations furthest from shore, with the lowest mean foraminif- eral densities (7 individuals/cm 3 ) and AEI (79) and the highest diversities (H9= 0.56). The Teluk Ketapang site was also the least subject to anthropogenic stressors. The spatial distribu- tions of foraminifera appeared to reflect the sedimentary environment and input of labile organic matter from anthropogenic sources. INTRODUCTION Benthic organisms, both macrofauna and meiofauna, have long been recognized as good bioindicators due to their limited movement, which can expose them to pollutants for prolonged periods. Benthic foraminifera are highly abundant meiofauna, sometimes making up 80% of the biomass (Snider et al., 1984), and are ubiquitous in nearly all marine environments (Sen Gupta, 2003). Their distribution is mainly affected by environmental factors in their microhabitat. The interplay among physical, chemical, and biological conditions allows certain species to thrive, while excluding others (Jorissen, 2003). Benthic fora- minifera are used in many efforts to monitor biological, chemical, and thermal pollution (Alve, 1995). Their abundance, preservation potential, diversity, environmental tolerances, wide distribution, and cost effective sample collecting have made foraminifera excellent monitoring indicators (Alve, 1995; Scott et al., 2001; Murray, 2006). This study uses physical and chemical parameters together with foraminiferal assemblages and distributions to assess coastal waters and sediment quality around Penang National Park. STUDY AREA The study was conducted in the coastal waters of Penang National Park, Penang Island, Malaysia (Fig. 1) at four sampling sites: Teluk Bahang, Teluk Aling, Teluk Keta- pang, and Pantai Acheh. The depth ranged between 1.5– 10 m, with predominantly muddy substrate at most stations. These coastal waters are influenced by two prevailing seasons from the northeast and southwest (Chua et. al., 2000). The northeast one brings monsoon rain from December–February, while during the southwest season (June–August) the island experiences dry weather. Sampling sites were based on the nature of human activities present within the region. Inshore fishing and floating-cage aquaculture are major economic activities in Teluk Bahang. Teluk Aling is situated in a sheltered coastal area next to Teluk Bahang. The only human activities nearby are related to the Centre for Marine and Coastal Studies (CEMACS), Universiti Sains Malaysia. Teluk Ketapang is a sheltered bay situated 3 km southwest of Teluk Bahang. There is no development along its intertidal area, and therefore, it is considered a less disturbed site. Finally the Pantai Acheh sampling site is situated further south, closer to the mangrove ecosystem (Balik Pulau) of the Pinang River. Major anthropogenic activities occur near Pantai Acheh, as mangroves has been cleared for aquaculture ponds and housing, and thereby contribute to the effluent (domestic, aquaculture, and agriculture) dis- charge into the river (Nurul Ruhayu, 2011). MATERIALS AND METHODS One hundred forty-four sediment and water samples were collected bimonthly between October 2010 and September 2011. These samples together with in situ measurements of temperature, salinity, dissolved oxygen, and pH were obtained along a transect (Fig. 2) from the low-tide line to 1200 m offshore at 200-m intervals. Bulk sediments were collected using a 603 60 Ponar grab. These sediments were 1 Centre for Marine and Coastal Studies, Universiti Sains Malaysia, 11800, Penang, Malaysia 2 School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia 3 School of Distance Education, Universiti Sains Malaysia, 11800 Penang, Malaysia 4 Correspondence author. E-mail: fim98181@hotmail.my Journal of Foraminiferal Research, v. 44, no. 2, p. 143–150, April 2014 143