Molecular, Fluorometric and Confocal Microscopy Analysis of Microbial Community Composition and Structure

National Institute for Water Resources, Water Resources Research Institute Program

3/1/2012 – 3/1/2013


While periodic assessment of the effect of the effluent from the Sand Island sewage outfall on the benthic invertebrate population has been performed (e.g. Bailey-Brock, Paavo, et al., 2002), there had not been an assessment of the possible shift in the marine microbial community structure. In the last published assessment of the microbial activity at the outfall (Novitsky and Karl, 1985), the investigators concluded: “Although the activity of the microbial populations does not seem to have been affected drastically by the input of sewage effluent, we have no indication of its effect on the microbial community structure. The fate of the large microbial community on the effluent itself is unknown.” This is a serious shortcoming, as a shift in the microbial community structure can be pathological and has serious ecological implications (Smith, 2007).

Since 1985, methods have been developed to analyze the microbial community structure at the outfall and control sites (Webster and Negri, 2006). The relationships between marine microbes and human health will increasingly be important, as human populations rise and NSF has made Oceans and Human Health a priority. The objective of this proposal was to assess the microbial community by analyzing the biological films that result for colonization and settlement of water column microbes and propagules. We used DNA analysis, pulse amplitude modulated fluorometry (PAM), and confocal microscopy to investigate whether the microbial community structure, which forms in one month on vertically positioned glass slides at a eutrophic site, is different from the microbial community at a control site. The research was carried out by two UH Manoa doctoral students, an undergraduate student, as well as a Junior Researcher and PI.

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Celia Smith