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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 a...

Two new species of Volvocalean green snow algae are described from Upstate New York, Chloromonas chenangoensis and Chloromonas tughillensis. According to rbcL sequence analysis, these species belong to a subclade of five snow species of Chloromonas that includes Cr. brevispina, Cr. nivalis and Cr. pichinchae. These species have zoosporangia/gametangia (cell packs) that are propelled by flagella. The life cycles of Cr. chenangoensis and Cr. tughillensis include a change in cell shape from oblong to spherical before the loss of the cell wall. Using 8-h laboratory experiments, a peak in the change of cell shape occurred at 4 h for Cr. chenangoensis and between 2 and 4 h for Cr. tughillensis after the onset of light, and this was followed by a decline in change of cell shape for both species. Spherical cells peaked between 6 and 8 h for Cr. chenangoensis and at 8 h for Cr. tughillensis. Maximum total matings occurred at 4 h for Cr. chenangoensis and 6 h for Cr. tughillensis, which was followed by a p...