The optimum pH of the green snow algae, Chloromonas tughillensis and Chloromonas chenangoensis, from Upstate New York

摘要

The optimum pH of two species of snow algae from Upstate New York were assessed by studying three axenic strains of Chloromonas tughillensis in a pH range of 3.0-7.0 and three non-axenic strains of Cr. chenangoensis in a pH range of 3.0-8.0. Growth was examined at 0.5 pH intervals. Cell counts at the termination of the experiments differed among strains and among pH intervals in individual strains for both species, and strains of Cr. tughillensis responded differently to changes in pH (p < 0.001) while strains of Cr. chenangoensis did not (p = 0.193). Cell counts and absorbance data for Cr. tughillensis indicated an optimum pH of 4.9-6.1 using regression analysis. Strains of Cr. chenangoensis exhibited higher but insignificantly different counts between pH 7.0 and 8.0 with maxima at pH 7.5, but pH optima were not determined. When the range was expanded to include pH 8.5-9.0, an optimal pH of 7.0-8.0 was determined for strain CU 722B, and this is the first snow alga reported to have an optimum alkaline pH. The highest absorbance values, however, occurred between pH 3.0-4.5 and pH 7.0-8.0. The pH values recorded in the field were 5.0- 5.3 for Cr. tughillensis and 6.7-7.6 for Cr chenangoensis.