Holothuria leucospilota or locally known as "Patola" is currently considered the most abundant sea cucumber species in Malaysia. This coral reef-dwelling species is not in danger of extinction in comparison to commercial sea cucumbers such as "gamat." However, overfishing activities in addition to lack of fishing regulations in Malaysia could put this species at risk of extinction in the future. It is important to conduct research on the sea cucumber community in Sarawak because the data can be used as reliable information for future research. Therefore, this study is carried out to quantify and estimate the Holothuria leucospilota population from an intertidal area of Satang Besar Island, Sarawak, Malaysia. Ten stations surrounding the island were selected as the location for this study. A total number of 203 individuals of Holothuria leucospilota were recorded and estimation of the population that inhabits the island's intertidal area was 609 individuals. RELATE test showed relationships between species population and water parameters, namely, temperature, salinity, and pH. Results from this study are important as a baseline data that might contribute to the sustainable management of Sarawak, Malaysia's sea cucumber in the future. Future work suggestions include addition of subtidal samples and other factors, namely, seawater nutrients and feeding environment, that should be done to better understand the population.
Gracilaria red algae are notable for their economic importance as agrophytes, sold as salad vegetable, and used as the base for selected food and nonalcoholic beverages. A wild population of Gracilaria exists in coastal areas of Sarawak, Malaysian Borneo, but there is only limited knowledge on species diversity and its abundance leaving the untapped economic potential of this resource. This study was carried out to determine diversity of wild Gracilaria populations in Lawas, Santubong, and Asajaya, Sarawak, using the combination of morphological character examination and 5′ region of the mitochondrial cytochrome c oxidase 1 (CO1-5P) gene analysis. Identification of the species using morphological characters revealed three species, namely, Gracilaria changii, G. blodgettii, and G. arcuata, had been collected from the sampling sites. However, based on 672 bp CO1-5P gene sequence analysis, all the three species were identified as G. blodgettii; besides, low genetic divergence values (0.17%–0.34%) were scored between samples in this study with the same species in GenBank. In the phylogenetic trees, all samples in this study group together with other G. blodgettii have high bootstrap values; thus, this species is monophyletic. This study implies that species identification of Gracilaria and other seagrass taxa which have a phenotypic plasticity problem should include the CO1-5P gene analysis as it is a reliable gene marker for species diversity assessment.
Red seaweed Gracilaria, one of the largest genus in Division Rhodophyta inhabits Sarawak coastal water. This study was designed to identify the species of Gracilaria using morphological approach and to assess selected water quality parameters in Gracilaria habitats. Three field samplings were carried out in Santubong and Asajaya, Sarawak from November 2013 to December 2014. Overall, three species were identified namely Gracilaria changii, G. blodgettii and G. coronopifolia, attached to net of cage culture in Santubong and root of mangrove trees in Asajaya. In addition, three different taxa of aquatic macroinvertebrates (polychaete, small crab, bivalve) and single species of red seaweed (Acanthophora sp.) were observed in Gracilaria assemblages. An estimate of 37% to 40% of the upper part of the cage net in Santubong was covered by seaweeds and only 16% to 20% in Asajaya’s mangrove. The study had provided better information on identification of Gracilaria and their habitat in Sarawak. Future work involving DNA barcoding of each species is in progress.
Highlight Research The present of microplastics is more than macroplastics on the Pasir Pandak Beach The existence of huge amount of smaller microplastics (<0.50 mm) were observed on this beach sediment Types of macroplastics found are fragment, foam, and fiber; while microplastics are fiber, filament, fragment, and foam The main polymers found are HDPE, PES, PP, and PS Clean Coast Index indicated Pasir Pandak Beach as an extremely dirty beach Abstract Pasir Pandak Beach is close to human settlements, resorts, and food stalls. It becomes a place for gathering of beachgoers especially during weekend. As a result, the beach became polluted with rubbish, particularly plastics (e.g., macro- and micro-plastics). Hence, this study was done to determine the occurrence of macro- and micro-plastics on the Pasir Pandak Beach, Kuching, Sarawak, Malaysia. Transect quadrat was used during the samples collection on the beach. The samples were then undergone the wet peroxide oxidation, filtering and classifying under dissecting microscope. Macroplastics were isolated for ATR-FTIR and SEM analyses, while microplastics were separated according to their sizes, colors, and types. Approximately 101.70 items/m2 of macro-plastics and 1084 items/m2 of micro-plastics were found in this study. Clean Coast Index (CCI) was also estimated and the calculated CCI value obtained was >20, which indicated as extremely dirty beach. Fragments of carpet/canvas/mat and hardware crate/item were the most abundance macroplastics found, followed by plastic ropes/fishing lines and bottle caps. HDPE, PES, PP, and PS were the main identified polymers. Fibers, filaments, fragments, and foams were identified for micro- and macro-plastics. Microplastics with smaller sizes of 0.25-0.50 mm were available abundantly and they comprise 63.47 % of the total microplastics found. Clear/white, black, and blue were the main colors for microplastics. SEM images presented that those adhering particles, grooves, pits, fractures, and flakes were the common patterns of degradation. No relationship was apparent between macro- and micro-plastics at each station. The abundance of macro- and micro-plastics showed that they were mainly controlled by the land-based input. As Pasir Pandak beach is busy with local communities and beachgoers, the presence of macro- and micro-plastics on the beach posing a severe threat for marine environment, thus further studies on the behavior of this emerging pollutant from beach to the seas are necessary.
Microplastics pollution has become a worldwide common problem. Despite the growing numbers in researches regarding the microplastics, the understanding of microplastics in the freshwater environment are still less. This paper overviews the present knowledge and findings on the occurrence of microplastics in water and sediment of the freshwater environments in Asia. The review also covers the size distribution, polymers, morphological characteristics and sources of microplastics to the freshwater systems. Perspective of the adsorption of heavy metals on the microplastics to the freshwater systems are also discussed in this review.
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