Honours and UROPS students AY2024/2025
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Leow Wei KaiMain supervisor: A/P Darren Yeo Chong Jinn Freshwater shrimps are one of the most dominant benthic invertebrates found in freshwater water bodies globally with at least 655 freshwater species identified globally currently. They inhabit a large range of habitats from various freshwater bodies such as lakes and streams to cave systems and even artificial structures such as floating docks and man-made ponds. Freshwater shrimps play crucial ecological roles in freshwater streams, such as in nutrient cycling and breaking down leaf litter. They are even capable of influencing the species composition of benthic communities. Within Singapore, the freshwater shrimp fauna is represented by three genera, namely Macrobrachium, Caridina, and Potamalpheops with a total of nine native species currently extant which live their entire life cycles in freshwater. These shrimps are predominantly found within the natural forest streams in Singapore, now largely restricted to protected nature reserves. Many surveys and assessments have been carried out in order to depict and describe the diversity of freshwater shrimps present in Singapore but little is known about the ecology of these shrimps. In particular, not much research has been published on characterising the associations they have with their habitats; such as how physicochemical variations in the water can affect their abundance. There has also not been any studies comparing the habitat associations between the three different families of freshwater shrimp in Singapore. The continued survival of freshwater shrimp species in Singapore is of concern given that a majority of the existing freshwater shrimp species are endangered. Therefore, this paper seeks to characterise and understand the habitats of Singapore’s freshwater shrimps, as well as study any habitat associations present, in Central Catchment Nature Reserve and the surrounding buffer parks to contribute towards local conservation efforts for native shrimps. Specifically, this study will explore the following research questions:
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Lim Yi En, BrennaMain supervisor: Dr. Maxine Allayne Darlene Mowe Microplastics, defined as plastic particles of diameter <5mm, have become ubiquitous in aquatic environments due to the increased manufacture and disposal of plastic products. The proximity of human settlements to freshwater bodies has increased the potential for the transfer of microplastics from the terrestrial environment into the aquatic environment, making it critical for a greater understanding of microplastics in freshwater systems and their impact on ecosystem health. In particular, aquatic macrophytes have been spotlighted as bioremediators due to the adhesion of microplastics to their surfaces, trapping large amounts of microplastic fragments. However, this poses a potential threat to invertebrate herbivores which feed on these macrophytes, as they might ingest microplastics along with the plant matter. In addition, as invertebrate prey are consumed in large numbers, the facilitation of trophic transfers of microplastics for bioaccumulation when moving up the food chain can occur. This study aims to quantify the extent and rate of uptake of microplastics from macrophytes by freshwater invertebrates through experimental means, shedding light on the interactions that might be affected due to the trophic transfer of microplastics through the food chain by answering four research questions:
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Ong Rae Lyn, MelissaMain supervisor: A/P Darren Yeo Chong Jinn Reservoirs are key landscape features in Singapore’s urban setting. Through a network of drains, canals and rivers, rainwater is funnelled into Singapore’s 17 reservoirs where two-thirds of Singapore’s land area act as water catchment. While engineered primarily for water storage and management, reservoirs have evolved into habitats where complex food webs thrive. Serangoon Reservoir was the 17th addition to Singapore’s 17 reservoirs in 2011 and was created by damming the mouth of Sungei Serangoon. Surveys before, during and after the construction of the dam showed an overall change in diversity and composition of fauna mostly attributed to the shift from estuarine to freshwater. Furthermore, biomanipulation trials were conducted recently. This study aims to investigate the changes in food webs and fish communities across time and space stable isotope analysis and gut content analysis. Additionally, it seeks to determine if these changes are associated with changes in biotic and abiotic factors.
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Shaylie Yu ShihuiMain supervisor: A/P Darren Yeo Chong Jinn Odonata (damselflies and dragonflies), with their aquatic nymphs and terrestrial adults, are important ecologically and as bioindicators of water quality and land use. Odonate diversity is relatively well studied in Singapore, including recent surveys of key conservation areas, the Bukit Timah Nature Reserve (BTNR) and the Nee Soon Swamp Forest (NSSF) within the Central Catchment Nature Reserve (CCNR). The last broad-based study of the overall CCNR, however, was conducted more than 30 years ago; since then, the CCNR has seen various changes including establishment of several peripheral nature parks to serve as buffers to increased human pressure. This study proposes to re-survey dragonflies and damselflies in the rest of CCNR (excluding NSSF) associated with forest and buffer park streams, to investigate possible changes in odonate abundance and distribution and the implications for the health of aquatic and terrestrial ecosystems within. Specifically, this study will address the following questions: (1) What is the abundance and diversity of adult dragonflies and damselflies in forest and buffer habitats? (2) Do environmental parameters differ between forest and buffer streams? (3) Are there patterns of association between environmental parameters and the abundance and diversity of adult dragonflies and damselflies? |
