Kayla Turek Thesis Defense: Project Description
Title: Behavior and Ecosystem effects of the invasive Asian clam (Corbicula fluminea) in urban streams
Invasive species can be detrimental to freshwater ecosystems. By completing laboratory and field studies to observe processes and behaviors of the invasive Asian Clam (Corbicula fluminea), I documented pathways whereby this invasive species impacts aquatic ecosystems under conditions typical of urbanized streams. The predominant pathways by which clams impacted nitrogen (N) cycling was through excretion thus increasing ammonium (NH4+) flux out of sediment, and through bioturbation, which increased nitrate (NO3-) diffusion to the sediment and dinitrogen gas (N2) production (i.e., denitrification). The effect was greater under urban conditions, where C. fluminea population density and water column NO3- were higher than in the rural stream. Environmental conditions also negatively impacted the clams’ physiology and mortality. The decline in clam condition and high mortality rates, particularly under high nutrient conditions, suggest that it may not be the tolerance of the individuals that allows for the persistence of successful populations, but the life history strategies of the species.
Conducting laboratory and field studies on clams’ ecosystem effects inspired questions about what factors control clams burial behavior. In laboratory experiments on clam behavior, I found that larger substrates impeded burrowing ability. Despite ease of movement in smaller substrates, clams did not preferentially choose one substrate over another or move laterally once buried. I also found that presence of predators did not affect burial speed or number of clams that buried unless the predator was frequently manipulating the clams. Learning how invasive species behave and how they affect the ecosystem is crucial to management and prevention, and I hope that my research will be of help in those efforts.
I would like to thank my advisor Dr. Timothy Hoellein and my committee members Dr. Martin Berg and Dr. Nancy Tuchman for helping me design and carry out this research and for all of their input and advice along the way. I would also like to thank my fellow graduate students Michael Hassett and Ashley Cook and the undergraduates Melaney Dunne, Ricardo Magallon, Joseph Gasior, and Adam Pink for their help in various aspects of this project. Finally, I would like to acknowledge Loyola University Chicago and Dr. Teresa Grande, graduate program director, for giving me this opportunity.
Kayla Turek was born in Canfield, Ohio. After completing her work at Canfield High School, she attended Thiel College, receiving a Bachelor’s of Arts degree in Conservation Biology in May, 2011. She entered the biology graduate program at Loyola University Chicago in August 2011. In May, 2013, she was married and relocated to Pittsburgh, Pennsylvania.
Dr. Timothy Hoellein
Dr. Martin Berg
Dr. Nancy Tuchman