The effects of temperature upon the reproduction and respiration of a marine obligate psychrophile

Abstract

The growth and respiration rates of a marine obligate psychrophile, Vibrio sp., were determined in a complex medium using optical density and viable counts and a polarized oxygen-electrode system. Growth rate was optimal at 7C and decreased at 10C, the maximum temperature for growth. Respiration increased continually from 1to 10C. Both growth and respiration rates were highly sensitive to small changes in temperature. For example, rates at 4C were 1.8 and 4.4 times higher than at 1C for growth and respiration, respectively. Growth efficiencies were calculated as generations per hour divided by respiration rate. Results indicated that the growth efficiency of this bacterium was much greater at the lower temperature range of growth.