LE3 .A278 1997

1997

Bell, Colin

Acadia University

Master of Science

Masters

Biology

Biology

A review of the present state of microbial ecology with emphasis on the Biolog system of community profiling: conventional topics, fatty acid profiling and nucleic acid techniques are discussed. Microbial communities from the Cornwallis estuary, Atlantic Canada, (45$\sp0$ 06$\sp\prime$N, 63$\sp0$ 24$\sp\prime$W), were characterized from late June to late September 1995, using Biolog GN community profiles. Communities were separated into three details by either being left whole (crude) or size fractionated by filtration to obtain the attached and free-floating portions. The continuous variable slope was used for principal component analysis (PCA). Slope is the result of curve fitting the optical density (OD) vs time graphs with the appropriate function for its shape. The PCA appears to indicate a shift in the structural and functional diversity midway through the summer. The June and July samples group in a similar, loose, fashion on all three axes of the PCA plot, with a noticeable shift occurring in the late July samples. The August and September samples are grouped in a tight cluster, indicating a high degree of similarity. The supporting data are in agreement with these observations. Plots of the mean corrected optical density (optical density minus the Al control well) show a distinction between the free-floating portion and the others. The metabolic profiles based on the Biolog system indicate a shift in the functional ability of the community, however they do not indicate if this functional shift is a result of physiological adaptation or a structural shift in community members. Additional data (total counts, total and fecal coliform counts, tritiated thymidine and viable counts) indicates both structural and functional involvements in the shift. The interpretation of the Biolog profile is ongoing. Determination of structural or functional influences on metabolic potentials are necessary before functional diversity measurements can be facilitated.

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