Abstract

During the summero f 1964 a taxonomica and ecological study was made of the desmids (microscopic green algae) found in Lily Lake. The study site is a subalpine lake in the Wasatch National Forest of the Uinta Mountains, Utah. The lake is located about one-half mile west of Trial Lake at an elevation of approximately 10,000 feet. The lake is an acidic, cold, lentic bog pond characteristic of this region. Desmids were collected at weekly intervals from seven sampling sites. The water temperature, pH, dissolved oxygen, light conditions and length of day from sunrise to sunset were recorded at the time of collection. Periphyton samples were obtained by scraping material from the stems and lower sides of leaves of water lilies, organic matter lying on the bottom of the lake, submerged logs and stems, dead sedge and grass leaves of the quaking peat, and organic matter of a floating peat mat. Surface samples were obtained by use of a plankton net. Small sheets of broken glass were suspended in the water as artificial habitats for desmid growth. There were 167 species collected representing seventeen genera of the family Desmidiaceae. Illustrations were made of every species collected. Ninety-four different species were found that have not been reported in Utah waters. The species were divided into five groups based on their percent frequency: (i) abundant (80-100%}, (ii) common(60- 79%), (iii) frequent (40-59), (iv) occasional (20-39%), and (v) scarce (5-19%). There were fourteen abundant species. four of these were observed in each to collection made: Buastrum Didelta, Triploceras gracile, Cosmarioum margaritiferum, and Xanthidium armatum var. fissum. There were twenty-two common species, twenty-four frequent species, forty-three occasional species, and sixty-four scarse species. Five genera contained the majority of species found. Cosmarium was represented with fifty one species; Closterium and Staurastrum each had twenty-five species; Micrasterias had sixteen species; and thirteen species were in the Euastrum genera. Xanthidium, Penium, Pleurotaenium, Arthrodesmus, Desmidium, Netrium, Triploceras, Hyalotheca, Sphaerozoama, Onychonema, Spondylosium and Gymnozyga were the remaining genera. There were thirty-seven species in this latter group. The natural habitats provided the best environment for the growth of desmids. Periphyton samples from the shallow water contained the largest number of species. Artificial habitats of glass sheets were especially favorable for the growth of Closterium lineatum, Closterium ralfsii var. hybridum and Closterium sp. (5). Few species were found free-floating where the lake was over six feet deep. As the pH, air, and water temperature increased during the growing season, the number of species collected increased, and as the water temperature decreased, oxygen increased, and the number of species collected decreased.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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