Determining the water quality of Bakun Reservoir 13 months after it operates at full supply level is crucial for better understanding of changes in the physicochemical parameters, which may enable the prediction of its effects on the survival of aquatic life in the reservoir. This study determined 13 physicochemical parameters at six stations within the reservoir at fixed depths. The results showed that the minimum 5 mg/L of dissolved oxygen (DO) required for sensitive aquatic organisms was recorded at 6 m depth. However, DO was not detectable at depths exceeding 7 m. The water was acidic at depths of more than 10 m. Turbidity and total suspended solids increased corresponding with depth. Inorganic nitrogen were predominantly in the form of ammonia-nitrogen, creating an unhealthy environment for aquatic life. Concentration of Chl-a was significantly higher at the subsurface water than 30 m depth in four out of six stations. The present study shows changes in water quality as compared to the pre-impounded period and 15 months after the filling phase, in particular, stratification of dissolved oxygen, thermocline conditions and alkalinity. The changes varied according to the distance from the dam and may have been influenced by existing land developments within the area such as the construction of the Murum Hydroelectric Dam, oil palm plantations and timber concessionares. Though the water quality might have deteriorated, further study is needed to determine if this condition will prolong.
Little is known about the diversity and roles of microbial communities in the South China Sea, especially the eastern
region. This study aimed to expand our knowledge on the diversity of these communities in Malaysian waters, as well as
their potential involvement in the breakdown or osmoregulation of dimethylsulphoniopropionate (DMSP). Water samples
were collected during local cruises (Kuching, Kota Kinabalu, and Semporna) from the SHIVA expedition and the diversity
of bacterial communities were analysed through the isolation and identification of 176 strains of cultured bacteria. The
bacteria were further screened for the existence of two key genes (dmdA, dddP) which were involved in competing,
enzymatically-mediated DMSP degradation pathways. The composition of bacterial communities in the three areas varied
and changes were mirrored in physico-chemical parameters. Riverine input was highest in Kuching, which was mirrored
by dominance of potentially pathogenic Vibrio sp., whereas the Kota Kinabalu community was more indicative of an
open ocean environment. Isolates obtained from Kota Kinabalu and Semporna showed that the communities in these
areas have potential roles in bioremediation, nitrogen fixing and sulphate reduction. Bacteria isolated from Kuching
displayed the highest abundance (44%) of both DMSP-degrading genes, while the bacterial community in Kota Kinabalu
had the highest percentage (28%) of dmdA gene occurrence and the dddP gene responsible for DMS production was
most abundant (33%) within the community in Semporna. To the best of our knowledge, this is the first study looking at
the diversity of culturable bacteria in coastal waters of East Malaysia and also their potential roles in the DMS(P) cycle.
Endophytic fungi provide protection to their host plant and the fungi often produce antimicrobial compounds to aid the host
fighting off pathogens. These bioactive compounds were secondary metabolites which were often produced as waste- or
by-products. In the present study, endophytic fungi isolated from mangrove plants and soils were characterized and their
antimicrobial production and bioremediation potential of heavy metals copper (Cu) and zinc (Zn) were assessed. Twelve
(12) isolated and identified endophytic fungi belonged to seven species; Penicillium, Curvularia, Diaporthe, Aspergillus,
Guignardia, Neusartorya and Eupenicillium. Antimicrobial activities of these 12 fungal endophytes were tested against
Gram negative bacteria; Bacillus subtilis, Staphylococcus aureus, Gram positive bacteria; Escherichia coli and fungi;
Candida albicans and Aspergillus niger among others. Two isolates (related to Guignardia sp. and Neusartoya sp.) showed
strong antimicrobial (and antifungal) activity whereas the rest showed no activity. Compounds were isolated from both
isolates and screened using HPLC. Both isolates displayed chemically very interesting chromatograms as they possessed a
high diversity of basic chemical structures and peaks over a wide range of polarities, with structures similar to Trimeric
catechin and Helenalin among others. For bioremediation assessment, the results showed maximum biosorption capacity
for two isolates related to Curvularia sp. and Neusartorya sp., with the former removing 25 mg Cu/g biomass and the
latter removing 24 mg Zn/g biomass. Our results indicated the potential of mangrove endophytic fungi in producing
bioactive compounds and also highlighted their potential for the treatment of heavy metal-contaminated wastewater.