Long-term and short-term variations of Escherichia coli population structure in tropical coastal waters

Abstract

In this study, monthly and daily samplings were carried out at Klang, an eutrophic estuary, and at Port Dickson, an oligotrophic coastal water system. Escherichia coli concentration was measured via culture method, and the phylogenetic structure of E. coli population was via Clermont typing. Average E. coli concentration at Klang was higher than Port Dickson (t = 2.97, df = 10, p \ 0.05), and daily sampling did not show any apparent temporal variation at both sites. At Klang, salinity was inversely correlated with coliform (R 2 = 0.216, df = 25, p \ 0.05), suggesting that river flow was a mode of transport for coliform. Although E. coli concentration was higher at the eutrophic site, E. coli population structure at both Klang and Port Dickson were similar and showed neither long-term nor short-term variations. This study showed the predominance of commensal groups A and B1 in tropical coastal waters of Peninsular Malaysia.

Archaeal community structure in the tropical coastal waters of Peninsular Malaysia

“…Although this study could not reveal temporal variability in the archaeal community structure, it presented a 'snap-shot' of the environment that was still useful for inter-site comparisons. Moreover, unlike temperate waters where temperature (Winter et al 2008) and seasonal variation (Herfort et al 2007) can influence Archaea communities, the main environmental drivers for microbes in tropical waters are monsoonal rainfall and storm events (Agawin et al 2003;Tan and Lee 2014;Vijayan and Lee 2014). As the samplings in this study were carried out during non-storm events, the community structure might reflect the general prevailing conditions.…”