Lee Co Sin
Email Address
tmslcs@nus.edu.sg
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Publication Bleaching response of Symbiodinium (zooxanthellae): Determination by flow cytometry(2012-10) Lee, C.S.; Wilson Yeo, Y.S.; Sin, T.M.; TROPICAL MARINE SCIENCE INSTITUTECoral bleaching is of increasing concern to reef management and stakeholders. Thus far, quantification of coral bleaching tends to be heavily reliant on the enumeration of zooxanthellae, with less emphasis on assessment of photosynthetic or physiological condition, these being often assessed separately by techniques such as liquid chromatography. Traditional methods of enumeration using microscopy are time consuming, subjected to low precision and great observer error. In this study, we presented a method for the distinction of physoiological condition and rapid enumeration of zooxanthellae using flow cytometry (FCM). Microscopy verified that healthy looking/live versus damaged/dead zooxanthellae could be reliably and objectively distinguished and counted by FCM on the basis of red and green fluorescence and light scatter. Excellent correlations were also determined between FCM and microscopy estimates of cell concentrations of fresh zooxanthellae isolates from Pocillopora damicornis. The relative intensities of chlorophyll and β-carotene fluorescences were shown to be important in understanding the results of increased cell counts in freshly isolated zooxanthellae experimentally exposed to high temperatures (34, 36, and 38°C) over 24 h, with ambient temperature (29°C) used as controls. The ability to simultaneously identify and enumerate subpopulations of different physiological states in the same sample provides an enormous advantage in not just determining bleaching responses, but elucidating adaptive response and mechanisms for tolerance. Therefore, this approach might provide a rapid, convenient, and reproducible methodology for climate change studies and reef management programs. © 2012 International Society for Advancement of Cytometry.Publication Adding coral rubble to substrata enhances settlement of Pocillopora damicornis larvae(2009-06) Lee, C.S.; Walford, J.; Goh, B.P.L.; TROPICAL MARINE SCIENCE INSTITUTESettlement preferences of Pocillopora damicornis larvae were examined on artificial substrata. Planulation of P. damicornis followed a lunar cycle and the release of larvae occurred after new moon. P. damicornis larvae had the highest rates of settlement within 3 days of being presented settlement substrata. Cumulative settlement gradually increased from 3 to 8 days, and post-settlement mortality was most frequent after 8 days. Settlement experiments showed greatest settlement preference to cement tiles containing 10% coral rubble. This study suggests that physical cues are important in the settlement process, which may be useful for coral reef rehabilitation projects. © 2009 Springer-Verlag.Publication The intestinal digesta microbiota of tropical marine fish is largely uncultured and distinct from surrounding water microbiota(NATURE PORTFOLIO, 2024-02-19) Soh, Melissa; Tay, Ywee Chieh; Lee, Co Sin; Low, Adrian; Orban, Laszlo; Jaafar, Zeehan; Seedorf, Henning; Dr Beng Hai, Adrian Low; BIOLOGY; TROPICAL MARINE SCIENCE INSTITUTE; BIOLOGICAL SCIENCESStudying the gut microbes of marine fishes is an important part of conservation as many fish species are increasingly threatened by extinction. The gut microbiota of only a small fraction of the more than 32,000 known fish species has been investigated. In this study we analysed the intestinal digesta microbiota composition of more than 50 different wild fish species from tropical waters. Our results show that the fish harbour intestinal digesta microbiota that are distinct from that of the surrounding water and that location, domestication status, and host intrinsic factors are strongly associated with the microbiota composition. Furthermore, we show that the vast majority (~97%) of the fish-associated microorganisms do not have any cultured representative. Considering the impact of the microbiota on host health and physiology, these findings underpin the call to also preserve the microbiota of host species, especially those that may be exposed to habitat destruction.