Aileen Tan Shau-Hwai

Source Type Evaluation of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments from the Muar River and Pulau Merambong, Peninsular Malaysia

This article is the most recent report of polycyclic aromatic hydrocarbons (PAHs) in the Muar River and Pulau Merambong, Peninsular Malaysia. A total of 16 priority pollutant PAHs in addition to methylphenanthrene among alkylated PAHs were analyzed in surface sediments during May 2013. Total PAHs ranged from 212 to 440 and 151 to 412 ng g−1 dw in sediments from the Muar River and the Pulau Merambong, respectively. The Muar River showed an increasing trend of PAH concentrations, while no previous data exist for the Pulau Merambong. Generally, mixed petrogenic and pyrogenic sources of PAHs with predominance of the latter were detected in the study area. Effective management of oil pollution has caused a drastic decrease in petrogenic sources of PAHs.

Forensic investigation of aliphatic hydrocarbons in the sediments from selected mangrove ecosystems in the west coast of Peninsular Malaysia.

Peninsular Malaysia has gone through fast development during recent decades resulting in the release of large amounts of petroleum and its products into the environment. Aliphatic hydrocarbons are one of the major components of petroleum. Surface sediment samples were collected from five rivers along the west coast of Peninsular Malaysia and analyzed for aliphatic hydrocarbons. The total concentrations of C10 to C36 n-alkanes ranged from 27,945 to 254,463ng·g(-1)dry weight (dw). Evaluation of various n-alkane indices such as carbon preference index (CPI; 0.35 to 3.10) and average chain length (ACL; 26.74 to 29.23) of C25 to C33 n-alkanes indicated a predominance of petrogenic source n-alkanes in the lower parts of the Rivers, while biogenic origin n-alkanes from vascular plants are more predominant in the upper parts, especially in less polluted areas. Petrogenic sources of n-alkanes are predominantly heavy and degraded oil versus fresh oil inputs.

Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediment from Muar River and Pulau Merambong, Peninsular Malaysia

Previous studies indicated that with increasing industrialization and urbanization, pollution problems have become more significant in Malaysia. West coast of Malaysia is more populated and urbanized than the east and therefore more susceptible to various pollutants. Surface sediment samples were collected from Pulau Merambong and Muar river, Peninsular Malaysia during May 2013 where 16 USEPA Priority Pollutants PAHs were analyzed using gas chromatography-mass spectrometry. Total PAHs in the sediments for Muar river ranged from 15.5 to 165.7 ng/g dw whereas the total PAHs for Pulau Merambong ranged from 38.6 to 122.8 ng/g dw. Due to rapid urbanization and motorization, Muar river showed an increasing trend of PAHs concentrations when compared to a study conducted about a decade ago. Pulau Merambong shows relatively lower PAHs concentrations as compared to other locations in Peninsular Malaysia. However, there is no previous data in Pulau Merambong to evaluate the trend in the petroleum hydrocarbons distribution and concentrations. In general, this study revealed that the lowest concentrations were detected in downstream of the Muar and Pulau Meranbong, respectively. This study also found abundance of high molecular weight (HMW) PAHs as compared to low molecular weight (LMW) PAHs suggesting predominance of pyrogenic PAH sources via atmospheric and long-range input. The ratio of LMW PAHs to HMW PAHs (LMW/HMW) were in the range of 0.05–0.33 indicating pyrogenic input and this is consistent with other diagnostic ratios.

Parasites of Blood Cockle (Anadara granosa Linnaeus, 1758) from the Straits of Malacca

ABSTRACT This is the first report on the parasites of blood cockle Anadara granosa from the Straits of Malacca. For a histopathological survey, samples were collected for 13 mo from 3 natural habitats: the west coast of Pulau Aman, Malaysia; the east coast of Banda Acheh; and the east coast of Lhokseumawe, Indonesia. After reviewing histological preparations, Nematopsis sp. was found in the connective tissue, gills, gonad, mantle, digestive glands, and foot; trematode sporocysts were identified in the gonads, stomach epithelium, mantle, digestive glands, and foot; and a turbellarian was observed in the stomach epithelium, gonads, digestive glands, mantle, and gills. Remarkable spatial differences were found in the parasitic communities of A. granosa of the Straits of Malacca; however, no apparent temporal variation in the prevalence of any parasite was evident. Nematopsis sp. infection was very common in A. granosa collected from Pulau Aman, with no clear host tissue damage. Trematode sporocysts were observed at all sites, and the gonads were completely lacking in some individuals as a result of infection. A turbellarian was detected without any evidence of pathological damage to the host. From the survey, only a trematode was detected as a potential threat to the natural stocks of A. granosa along the coasts of the Straits of Malacca. Further study should be carried out to identify the specific taxonomic affiliation of the parasites.

Carbonate mineralogy of a tropical bryozoan biota and its vulnerability to ocean acidification

ABSTRACT Decreasing pH levels in the world’s oceans are widely recognized as a threat to marine life. Bryozoans are among several phyla that produce calcium carbonate skeletons potentially affected by ocean acidification (OA). Depending on species, bryozoan skeletons can consist of calcite, aragonite or have a bimineralic combination of these two minerals. Aragonite is generally more soluble in seawater than calcite, making aragonitic species more vulnerable to OA. Here, for the first time we use Raman spectroscopy to determine the mineral composition of a tropical bryozoan biota. Compared with bryozoan biotas from higher latitudes in which calcite predominates, aragonite was found to occur in a much higher proportion of the 22 cheilostome bryozoan species collected from the shorelines of Penang and Langkawi in Malaysia, where 46% of species are calcitic, 41% aragonitic and 13% bimineralic. All but one of the aragonitic or bimineralic species belong to the ascophorans, whereas calcitic skeletons characterized most of the anascans, many of which are primitive ‘weedy’ malacostegines. These results suggest a relatively high vulnerability of tropical bryozoan faunas to OA, with the weedier taxa likely to be least impacted.

Systematics, genetics, and biogeography of intertidal mites (Acari, Oribatida) from the Andaman Sea and Strait of Malacca

Abstract This study demonstrates for the first time the presence of marine‐associated mites in the Andaman Sea and Strait of Malacca and reveals a relatively high diversity of these taxa with six species from two different families: Selenoribatidae and Fortuyniidae. Indopacifica, a new genus of Selenoribatidae, is described from Thailand and Malaysia, with two new species, Indopacifica pantai n. sp. and Indopacifica parva n. sp. The genus is characterized by the unique combination of following characters: lacking lamellar ridges, incomplete dorsosejugal suture, fourteen pairs of notogastral setae, and presence of epimeral foveae. A phylogenetic reconstruction based on 18S ribosomal RNA sequences clearly confirms the distinctness of the new genus Indopacifica and places it close to the genus Rhizophobates. The lack of molecular genetic data of possible relatives impedes a clear assessment, and hence, we emphasize the need for further combined approaches using morphological and molecular genetic sequence data. All species show wide distribution areas within this geographic region suggesting that these taxa are good dispersers despite their minute size and wingless body. Molecular genetic data demonstrate recent gene flow between far distant populations of I. pantai n. sp. from the coasts of Thailand and two islands of Malaysia and hence confirm this assumption. The seasonally changing surface currents within this geographic area may favor hydrochorous dispersal and hence genetic exchange. Nevertheless, morphometric data show a slight trend to morphological divergence among the studied populations, whereas this variation is suggested to be a result of genetic drift but also of habitat differences in one population of Alismobates pseudoreticulatus.