2025 Luc Ector Award – Joy Jackson
Investigating the Stephanodiscus niagarae vs. S. reimeri populations in West Lake Okoboji
Endemic species are restricted to specific geographic regions and often arise through extended periods of isolation, which can promote specialized adaptations but also increase sensitivity to environmental change. One aspect of my research focuses on the endemic freshwater diatom Stephanodiscus reimeri, a member of the Stephanodiscus niagarae species complex known only from the Iowa Great Lakes. Although closely related to the widespread Stephanodiscus niagarae, both species occur within the same lake system, suggesting coexistence rather than competitive exclusion. Using eight sediment cores spanning the last ~140 years, I will examine how these taxa have coexisted through time by tracking changes in species composition and diatom cell size across sites and sediment core depth. This work combines light microscopy and scanning electron microscopy (SEM) to ensure accurate species identification and detailed valve characterization, while size-based analyses are used to evaluate responses to nutrient enrichment and eutrophication. Together, these data will clarify how recent historical dynamics and environmental change shape the persistence of closely related diatom species in freshwater ecosystems.
My name is Joy Jackson, and I am a PhD student in the Department of Earth and Environmental Sciences at the Univer
sity of Kentucky. I earned my bachelor’s degree in Biology from Ursuline College in Ohio, where research in marine ecosystems sparked my broader interest in aquatic systems and freshwater lakes. I went on to complete my master’s degree at John Carroll University in Ohio (United States), working with Dr. Jeff Johansen on a diatom periphyton algal survey in Lake George, which solidified my interest in diatom ecology and microscopy. I am currently working with Dr. Trisha Spanbauer, having begun my doctoral research at the University of Toledo and continuing my work at the University of Kentucky. My research focuses on diatom communities in freshwater systems and how they respond to environmental change across space and time. This includes studies of diatoms in the western basin of Lake Erie supported by Ohio Sea Grant, sediment-core diatoms from the western basin of Lake Erie in collaboration with the NOAA GLERL, and diatom assemblages preserved in sediment cores from West Lake Okoboji, Iowa to investigate long-term ecological change.
I am sincerely grateful to the International Society for Diatom Research for the 2025 Luc Ector Bursary Award. This support will allow me to expand my microscopy and SEM skills, which are essential for diatom taxonomy, and will directly strengthen my research on diatom communities and populations. I am thankful for this opportunity and for the support of my development as an early-career diatom researcher.