Effect of salt and urban water samples on bacterivory by the ciliate, Tetrahymena thermophila

• Published in: Environmental pollution (1987) Vol. 158; no. 2; pp. 502 - 507
• Main Authors: St Denis, C.H., Pinheiro, M.D.O., Power, M.E., Bols, Niels C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2010; Elsevier
• Subjects: Analysis of Variance; Animal, plant and microbial ecology; Applied ecology; Bacterivory; Biological and medical sciences; Ciliates; Deicing; Ecotoxicology, biological effects of pollution; Escherichia coli - metabolism; Feeding Behavior - drug effects; Feeding Behavior - physiology; Food Chain; Fundamental and applied biological sciences. Psychology; General aspects; Green Fluorescent Proteins - metabolism; Reference waters; Road salt; Salt acclimation; Sodium Chloride - toxicity; Tetrahymena thermophila - drug effects; Tetrahymena thermophila - physiology; Toxicology; Urban creek; Deicing; Reference waters; Road salt; Toxicology; Urban creek; Ciliates; Bacterivory; Salt acclimation; Protozoa; Highway; Urban area; Salt; Pollution; Tetrahymena thermophila; Environment; Ciliata; Adaptation
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2009.08.014

The effect of road salt on the eating of bacteria or bacterivory by the ciliate, Tetrahymena thermophila, was followed in non-nutrient Osterhout's solution with Escherichia coli expressing green fluorescent protein. Bacterivory was impaired at between 0.025 and 0.050% w/v but the ciliates appeared to have normal morphologies and motilities, whereas at above 0.1%, bacterivory was blocked and many ciliates died. By contrast, E. coli remained viable, suggesting salt could alter predator–prey relationships in microbial communities. In nutrient medium, salt was not toxic and the ciliates grew. After growth in salt, ciliates consumed bacteria in 0.2% salt, indicating the salt acclimation of bacterivory. Bacteria and ciliates were added to urban creek samples to compare their capacity to support exogenous bacterivory. Even though samples were collected weekly for a year and be expected to have fluctuating salt levels as a result of deicing, all creek samples supported a similar level of bacterivory. Road salt at some concentrations inhibits bacterivory by ciliates, and thus potentially could alter the microbial food web.