The effect of salinity on the number of food vacuoles formed over time in Tetrahymena thermophila

Abstract

Many organisms require a specific salinity in their environment to grow and reproduce and changes to the salinity concentration can have drastic effects on their survival. The ciliate Tetrahymena thermophila is typically found in freshwater environments, thus, the objective of our experiment was to determine if salinity affects the number of food vacuoles present over time. We hypothesized that higher salinity will negatively affect the number of food vacuoles formed over time in T.thermophila. T.thermophila was placed in 0 mM, 5 mM and 100 mM NaCl solutions and vacuole number was observed 20, 40 and 60 minutes into the treatments. We found that the 0mM treatment group exhibited positive growth over time and the higher salinity treatment groups exhibited no significant positive vacuole formation over time. T.thermophila did not exhibit any vacuole growth in 100mM salinity treatment at any time point, indicating this salinity is above their upper tolerance for vacuole formation. This significant difference in food vacuole numbers allows us to reject the null hypothesis that higher salinity does not affect the number of food vacuoles formed over time in T. thermophila.