W. O. Wan Maznah

Aquatic pollution assessment based on attached diatom communities in the Pinang River Basin, Malaysia

The diatom communities collected from artificial substrates (glass slides) at 12 sampling sites along Pinang River Basin were analysed. Species composition was highly variable among sampling sites, and the highest diversity value (mean H′ = 3.56 bit/individual) and species richness (mean S = 17.32) was recorded at a polluted station in an estuary, which received salt-water intrusion during high tide. The downstream sampling stations were heavily organically polluted with Saprobic Index values ranging between 2.81 and 3.10, while upstream stations were relatively clean with Saprobic Index values recorded between 1.40 and 1.96. The diatom community structure and the specific sensitivity of certain diatom species can be related to the degree of water quality in Pinang River Basin. The abundance of certain diatom species could be used as biological indicators to measure impacts of river pollution.

Biosorption of copper and zinc by immobilised and free algal biomass, and the effects of metal biosorption on the growth and cellular structure of Chlorella sp and Chlamydomonas sp isolated from rivers in Penang, Malaysia

In this study, the biosorption of copper and zinc ions by Chlorella sp. and Chlamydomonas sp. isolated from local environments in Malaysia was investigated in a batch system and by microscopic analyses. Under optimal biosorption conditions, the biosorption capacity of Chlorella sp. for copper and zinc ions was 33.4 and 28.5 mg/g, respectively, after 6 hr of biosorption in an immobilised system. Batch experiments showed that the biosorption capacity of algal biomass immobilised in the form of sodium alginate beads was higher than that of the free biomass. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed that copper and zinc were mainly sorbed at the cell surface during biosorption. Exposure to 5 mg/L of copper and zinc affected both the chlorophyll content and cell count of the algal cells after the first 12 hr of contact time.

Assessment of heavy metal pollution in surface sediments of the Bayan Lepas area, Penang, Malaysia

This study aimed to evaluate the spatial and temporal distribution of heavy metals (Cd, Cr, Cu, Co, Fe, Pb, Ni, V, and Zn) in the sediments of Bayan Lepas Free Industrial Zone of Penang, Malaysia. Ten sampling stations were selected and sediment samples were collected during low tide (2012-2013). Metals were analyzed and the spatial distribution of metals were evaluated based on GIS mapping. According to interim sediment quality guidelines (ISQG), metal contents ranged from below low level to above high level at different stations. Based on the geoaccumulation index (Igeo) of sediment, sampling stations were categorized from unpolluted to strongly polluted. The enrichment factor (EF) of metals in the sediment varied between no enrichment to extremely high enrichment. The potential ecological risk index (RI) indicated Bayan Lepas FIZ was at low risk.

The Effect of Seasonal Changes on Freshwater Fish Assemblages and Environmental Factors in Bukit Merah Reservoir (Malaysia)

Abstract Seasonal changes of freshwater fish assemblages and environmental factors in Bukit Merah Reservoir were carried out from January-February 2013 (dry season) to March-April 2013 (wet season) by measuring several physico-chemical parameters such as dissolved oxygen (DO), water temperature, pH, water conductivity, total dissolved solids (TDS) and water clarity. 19 fish species comprising of 10 families were collected by using experimental gill nets with different mesh sizes at four different sampling stations. Mean CPUE for total catch and biomass were significantly different between dry and wet season (p < 0.05). Based on a T-test analysis, water temperature, pH and conductivity were significantly different (p < 0.05) between seasons whereas a one-way ANOVA displayed a significant difference in TDS and water clarity between sampling stations (p < 0.05), implicating that those factors did not give major influence towards other parameters in a man-made reservoir. From all fish species studied, only mean CPUE for individuals (CPUEn) of Osteochilus vittatus and Oxygaster anomalura had a significant difference between seasons (p < 0.05); probably an indicator of their migration season ZUSAMMENFASSUNG Auswirkungen saisonaler Schwankungen in Gemeinschaften von Süßwasserfischen und Umweltfaktoren im Bukit Merah Speicher (Malaysia). Saison gebundene Schwankungen in Gemeinschaften von Süßwasserfischen und Umweltfaktoren wurden im Bukit Merah Speicher von Januar-Februar 2013 (Trockenzeit) bis März-April 2013 (Regenzeit) untersucht. Dabei wurden einige physikalisch-chemische Parameter wie gelöster Sauerstott (DO), Wassertemperatur, pH, Leitfähigkeit, gelöste Feststoffe insgesamt (TDS) und Wassertransparenz gemessen. 19 Fischarten aus 10 Familien wurden mit Kiemennetzen unterschiedlicher Maschenweite an vier Probestellen gesammelt. Der mittlere CPUE-Wert für den Gesamtfang und die Biomasse war signifikant unterschiedlich in der Trocken- und Regenzeit (p < 0,05). Auf Grund einer T-Test Analyse zeigten sich bei Wassertemperatur, pH und Leitfähigkeit signifikante Unterschiede (p < 0,05) zwischen Trocken- und Regenzeit, während TDS und Wassertransparenz nur signifikante Unterschiede zwischen den Probestellen (p < 0,05) von einem Einweg ANOVA zeigten, woraus sich ergibt, dass diese Faktoren keinen großen Einfluss gegenüber anderen Parametern in einem künstlichen Wasserspeicher haben. Von allen untersuchen Fischarten war allein der mittlere CPUE-Wert für Individuen (CPUEn) bei Osteochilus vittatus und Oxygaster anomalura signifikant unterschiedlich zwischen den beiden Jahreszeiten (p < 0,05), was wohl ein Indikator für deren Migrationszeit ist Rezumat Efectul schimbărilor sezoniere asupra ihtiocomunităților dulcicole și a factorilor de mediu în lacul de acumulare Bukit Merah (Malaezia). Prezentul articol se bazează pe cercetări efectuate din lunile ianuarie-februarie 2013 (sezonul secetos) în martie-aprilie 2013 (sezonul umed) prin măsurarea parametrilor fizicochimici, precum oxigenul dizolvat (DO), temperatura, transparența și conductivitatea apei, pH, materia solidă dizolvată totală (TDS). 19 specii de pești din 10 familii au fost colectate cu ajutorul unor plase experimentale cu diferite mărimi ale ochiurilor în patru stații de eșantionare diferite. CPUE mediu pentru captura totală și biomasa au diferit semnificativ între sezonul secetos și cel umed (p < 0,05). Conform analizei T-test, temperatura, conductivitatea și pH-ul au variat semnificativ (p < 0,05) de la un sezon la altul în timp ce TDS și transparența au variat semnificativ de la o stație la alta (p < 0,05) după ANOVA, ceea ce înseamnă că acești factori nu au avut influență majoră față de alți parametri în acest lac artificial. Dintre toate speciile studiate, doar CPUE mediu individual (CPUEn) la Osteochilus vittatus și Oxygaster anomalura au variat semnificativ între sezoane (p < 0,05), probabil indicând sezonul de migrație.

Laboratory measurement: Chlorophyll-a concentration measurement with acetone method using spectrophotometer

Chlorophyll-a is an important factor in photosynthesis of microalgae. The concentration of chlorophyll-a in microalgae can be used to analyse and investigate the density and biomass of microalgae in the ecosystem. This is because microalgae are primary producer in the food web in freshwater and ocean. Thus, an accurate estimate of chlorophyll-a concentration in microalgae is very significant. In this study, the samples of microalgae were collected from Tasik Harapan and Tasik Aman, USM Penang, Malaysia. The samples were tested using 90% acetone method by using spectrophotometer (model HITACHI U-1900) to record the absorbance values with selected wavelengths namely 750 nm, 664 nm, 647 nm, and 630 nm The results showed that the chlorophyll-a concentration in microalgae increased when the absorbance was increased. The chlorophyll-a concentration in microalgae depended on several factors such as amount of sunlight available, total phosphorus (TP), water flow, light, catchment area, water depth, weather, and other physical factors. This study determined the value of chlorophyll-a concentration in microalgae collected from Tasik Harapan and Tasik Aman, USM Penang. The highest and the lowest chlorophyll-a concentration were recorded in this study. The spectrophotometer with 90% acetone method successfully determined the maximum and minimum sensitivity of chlorophyll-a concentration within the wavelengths tested.

Lentic and lotic assemblages of zooplankton in a tropical reservoir, and their association with water quality conditions

Zooplankton assemblages in relation to water quality parameters at lentic and lotic habitats of Air Itam Reservoir, Penang, Malaysia, were analysed. Five sampling stations were designated, including three stations located in the reservoir (Stations A, B, and C) and two stations in the upstream inflow and downstream outflow (Stations D and E, respectively). The most common and dominant zooplankton found in the lake were Polyarthra vulgaris, Ceriodaphnia cornuta, Mesocyclops leuckarti, and Thermocyclops crassus. Water Quality Index, calculated as recommended by the Malaysian Department of Environment, ranged between 88.46 and 93.6, showed that the reservoir was clean. Low numbers of species and value of the Shannon–Wiener Diversity Index were recorded at stations located upstream and downstream of the reservoir. Cluster analysis based on the abundance of zooplankton species distinguished the sampling stations into two groups (lentic and lotic groups, comprised of Stations A, B, and C; and Stations D and E, respectively). This study showed that zooplankton occurrence and abundance were associated with the quality of their environment, and zooplankton community provides information about the reservoir ecosystem, thus reflecting the importance of biomonitoring in lake assessment and management.

Estimating the chlorophyll a concentration of phytoplankton from an empirical analysis

Chlorophyll a concentration plays an important role as an indicator for biomass and abundant of phytoplankton in ecosystem. In this study, an empirical model, based on actual water quality of phytoplankton measurement was used to estimate chlorophyll a concentration based on optical properties of reflectance. The study area was carried out at Tasik Harapan, Universiti Sains Malaysia (USM), Penang, Malaysia. The proposed algorithm was based on the reflectance model. This reflectance model was a function of inherent optical properties of water which was related to chlorophyll a concentration. Concentration of chlorophyll a can be estimated by creating a model that correlates between chlorophyll a and radiance. Freshwater reflectance is dependent on the absorption coefficient and backscattering coefficient of their inherent optical properties. The reflectance values were used in the water quality algorithm calibration. The ability of the proposed algorithm was investigated based on correlation coefficient between actual and predict of chlorophyll a concentration. These algorithms are considered excellent based on the values of the correlation coefficient, R are 0.7519 and 0.8417 when tested on the samples.