Date of Award


Degree Type


Degree Name

Master of Science (MS)

First Advisor

Dr. Jeffrey Johansen


Lake George is an oligotrophic lake that has been monitored by the International Biological Monitoring Program (IBM) since the 1960s. The 51 km long lake is separated into two deep basins, one in the south where the major stream inputs are located, and one in the north where the lake feeds the La Chute River, which empties into Lake Champlain. The two basins are separated by a shallow channel named the “Narrows.” The southern basin has experienced a higher level of development than the northern basin. The aim of this study is to characterize the diatom assemblages in the northern and southern basins to determine if an enrichment signal can be discerned in the diatom communities. The periphyton communities occurring on artificial substrates in both basins were studied with three sampling periods in the summer of 2019. Principal Component Analysis (PCA) clearly separated the basins based on diatom communities in all three sampling periods. Trophic indicator status for diatom species reported by Van Dam, the Trophic Diatom Index formulated by Kelly and Whitton, and Shannon Diversity for the diatom communities were calculated to determine the nature of the differences that caused separation in the PCAs. Lake George oligotrophic status is supported by the analysis of diatom communities in this work. However, my analyses indicate that the southern basin has a slightly greater enrichment than the northern basin, and our work could serve as an early warning that cultural eutrophication may be in the preliminary stages in this economically important lake.

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