Effect of salinity on the growth of Chlamydomonas reinhardtii

Abstract

Over the years, human activities have led to increasingly saline conditions within freshwater ecosystems. This increase in salinity can have an impact on microorganisms including Chlamydomonas reinhardtii. It was hypothesized that increasingly saline conditions would lower growth rate and limit overall population size for this species of algae. A culture of Chlamydomonas at population equilibrium was diluted and subjected to three different conditions: ideal growth medium, 0 mM NaCl, 150 mM NaCl and 300 mM NaCl growth medium respectively. Three populations were developed in each condition for statistical significance. After 14 days, the cell density within each individual culture was counted using a hemocytometer, and data was analyzed using an ANOVA test. The results showed a negative correlation with increasing salinity and population size. However, this correlation was shown to be insignificant by way of statistical analysis. The lack of significance can be explained by many experimental errors stemming from a difficulty in homogenizing cell cultures for analysis. These errors in tandem with the statistical analysis results led to us being unable to validate or invalidate our initial hypothesis. Further research into the effect of increasingly saline conditions on Chlamydomonas reinhardtii is necessary to determine a significant relationship.