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General Session 3: Biological oceanography & global change |
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Vibrio community in the coastal waters of Peninsular Malaysia
GS3-58-S
Yiyou Wong* , Institute of Ocean and Earth Sciences, Institute of Graduate Studies, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Lee Choon Weng, Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Bong Chui Wei, Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Presenter Email: yiyou798@gmail.com
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| Vibrio spp. is a ubiquitous member of different water ecosystems, like coastal waters, open oceans, estuaries, brackish waters and even extreme habitats including Antarctic and Arctic Oceans. Most members within this genus are important. Ecologically, this group of bacteria display seasonality affected by physical parameters, mainly temperature and salinity. However, in tropical countries like Malaysia, surface seawater temperature is generally constant all year long, allowing other possible environmental variables to drive vibrio dynamics. This current study is part of our investigation into the ecology of vibrios. At two different sites (Port Klang and Port Dickson), culturable vibrios were estimated on a monthly basis from September 2013 to October 2015 using membrane filtration and spread plating technique on TCBS agar. Vibrio colony forming units (cfu) from both sites were similar (P= >0.05), with abundance ranging from 20 to 655 cfu ml̶ 1 in Port Dickson and 15 to 2395 cfu ml-1 in Port Klang. The estimated vibrio abundance represented 6.5±6.5% of total culturable bacteria on Marine Agar in Port Dickson, whereas in Port Klang, it accounted for only 2.7±2.6% of the total culturable bacteria. In this study, the free-living vibrios were assumed as vibrios cultured from the <2.0 μm fraction whereas the attached vibrios were measured as the difference between total vibrios and free-living vibrios. The attached (>2.0 μm) vibrios detected from both sites were greater in number than the free-living (<2.0 μm) fractions where 90±15% of vibrios from Port Dickson and 91±13% from Port Klang were attached. Over a period of six months, vibrios were also isolated and identified via 16S rRNA sequence after PCR amplification using universal primers. Of this, 210 and 233 isolates were sequenced from Port Dickson and Port Klang, respectively and a total of 22 species were identified from Port Dickson whereas 16 species from Port Klang. Through one-way ANOSIM analysis, the community structure from the two study sites resembled each other despite the different nutrient profiles detected. Species isolated between total and free-living community of Port Dickson were different (ANOSIM, R=0.4894, P <0.05). Among the species isolated, the total fractions were dominated by V. communis whereas V. rotiferianus was most frequently found in the free-living fractions of both sites. |
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