How does infection with the digenean trematode, Cercaria opaca, modify benthic community structure by altering the behavior of its influential host, Littoraria irrorata Public Deposited

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  • May 15, 2019
  • Henderson, Abigail
    • Affiliation: College of Arts and Sciences, Curriculum in Environment and Ecology, Environmental Science
  • Shifts in temperature, salinity, and mean water level due to sea level rise in intertidal zones have a direct impact on parasitism in marine organisms. Littoraria irrorata, the marsh periwinkle, is a gastropod that lives in soft sediment intertidal flats. L. irrorata utilizes Spartina alterniflora as a food source, creating lacerations in the blades of cordgrass and farming fungus for nutritional input through nutrient excretion. When infected with Cercaria opaca, a digenian trematode parasite, the periwinkle exhibits behavioral alterations, including lower grazing rates on Spartina irrorata. Experimentation on the indirect effects of meiofauna-benthic invertebrate species that serve as a vital food source for higher trophic levels and facilitate biomineralization of organic matter and enhanced nutrient regeneration- due to parasitism of Littoraria showed significant results. Presence of L. irrorata infected with C. opaca exhibited an ability to mitigate S. alterniflora die-off (p=4.48E-05). A bivariant analysis taking square root transformed data and comparing it to treatments across time in JMP revealed a linear relationship between change in biomass of S. alterniflora and meiofauna abundance (R2 = .558). Presence of infected snails in plots reduced variability in meiofauna over time, as compared to noninfected plots, which exhibited a significant variability of initial abundance to final change, especially at higher initial abundances (P=0.0068). Data shows a positive linear relationship between Uca pugnax and meiofauna abundance, suggesting that species, particular nematodes, utilize the burrows of fiddler crabs for protection, oxygen in normally hypoxic or anoxic soil, and resources (R=0.788). Time, treatment, and the interaction between the two are significantly different for meiofauna in all treatments except for no snail plots, suggesting prominent meiofauna taxa to shift dramatically, especially in uninfected plots (significance for uninfected plots, infected plots, and open plots were p=0.01, 0.005, 0.03, respectively).Overall, data suggests that increased rates of parasitism in Littoraria irrorata in soft sediment mudflats are beneficial to the ecosystem, as Spartina offers a myriad ecosystem services for humans and the environment, and increased meiofauna diversity and abundance allow for biomineralization of organic matter while offering a food source for a variety of organisms. Parasites, which have been seen to increase with global warming due to more favorable conditions, may be an unlikely benefactor for shoreline protection in coming years.
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Rights statement
  • In Copyright
  • Noble, Rachel T.
  • Bachelor of Science
Academic concentration
  • Environmental Science
Honors level
  • Honors
Degree granting institution
  • University of North Carolina at Chapel Hill
Graduation year
  • 2018
  • English

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