Mahurin Honors College Capstone Experience/Thesis Projects

Department

Biology

Document Type

Thesis

Abstract

Zooplankton are small aquatic animals that serve an important role in transferring energy from phytoplankton to higher trophic levels. The zooplankton community composition in Barren River Lake from 2008 and 2020 was compared. A field study was conducted to not only describe the seasonal population dynamics of zooplankton in Barren River Lake, but also to determine if an invasive zooplankton, Daphnia lumholtzi, was present. While D. lumholtzi was found throughout Barren River Lake in 2008, it was absent from both resampled sites in 2019 and 2020. This, along with erratic patterns of emergence in several other zooplankton species, indicates that species composition in Barren River Lake can be highly variable. Daphnia lumholtzi is characterized by a long spine that aids it in avoiding predation from invertebrate predators and small fish. To test if the spines were causing damage to the mouths of small fish, a series of feeding trials were conducted with Bluegill feeding on introduced D. lumholtzi, or Daphnia pulex, a native species. Juvenile Bluegill from the feeding trials were dissected, and their buccal cavities were observed under a scanning electron microscope (SEM) to check for any spine-inflicted damage. In the feeding trial, Bluegill readily ate both D. pulex and D. lumholtzi. Examination of the tongues of the fish showed no difference in physical damage (scraping of the epithelium) between the fish consuming D. lumholtzi and D. pulex. Continued monitoring of the zooplankton community of Barren River Lake is critical to understand the impacts of D. lumholtzi.

Advisor(s) or Committee Chair

Philip Lienesch, Ph.D.

Disciplines

Biology | Terrestrial and Aquatic Ecology | Zoology

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