Date of Award

2005

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Charles C. Somerville

Second Advisor

Frank L. Binder

Third Advisor

Ronald E. Gain

Abstract

During 2003, water samples from the Big Sandy watershed were collected in conjunction with the United States Army Corps of Engineers (USACE). Objectives were to determine the effects of dams on bacterial populations and to test a bioindicator of water quality based on antibiotic-resistant and fecal indicator bacteria. Thirty-five samples were taken each season within the Big Sandy Watershed, which includes six USACE dams. Total cultivable, ciprofloxacin-resistant, erythromycin-resistant, tetracycline- resistant, total coliform, and fecal coliform bacteria were enumerated. Data on water chemistry and physical parameters were collected by the USACE in the spring and summer seasons. Antibiotic-resistant bacteria and fecal coliform data were used to assign a site impact score (-4 to +4). The scores show significant differences between upstream (n = 17) and downstream (n = 18) sites in two of three sampling periods analyzed (spring, P < 0.01; summer, P < 0.05; fall, P = 1.0). Sites downstream of dams typically had lower bacterial counts and negative impact scores; whereas, sites upstream had higher bacterial counts and higher impact scores. A significant correlation was repeated in the spring and summer seasons between ciprofloxacin-resistant bacteria and dissolved Kjeldahl Nitrogen (spring, P < 0.01; summer, P < 0.05) and between turbidity and erythromycin-resistant bacteria (P < 0.01). Data on turbidity and weather conditions indicate that bacteria are highly correlated to turbidity, especially under high water and rainfall conditions. This positive correlation suggests an association between bacteria and particulates. The microbiological analyses suggest dams allow particulates and associated bacteria to settle out, leading to an apparent decrease in water impact indicators and bacterial counts.

Subject(s)

Big Sandy Watershed (Ky. and W. Va.)

Water quality.

Water - Microbiology.

Dams.

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