Date of Completion

7-28-2014

Embargo Period

7-20-2014

Keywords

Oyster, Fouling, Growth, Competition, Predation, Temperature

Major Advisor

Dr. Robert Whitlatch

Associate Advisor

Dr. Evan Ward

Associate Advisor

Dr. Hans Dam

Associate Advisor

Dr. Richard Osman

Field of Study

Oceanography

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Changes in temperature with global warming can facilitate biological invasions, cause species range shifts, alter community composition, and affect the growth rates and competitive abilities of many marine and terrestrial species. However, few studies take into account latitudinal variability in thermal responses or interactions between species. This dissertation focuses on the impact of temperature on predator-prey and competitive relationships in coastal epibenthic marine communities. Eastern oysters (Crassostrea virginica) are economically and ecologically important, but their relationship with a major predator, the oyster drill Urosalpinx cinerea, is not well understood. Three chapters of this dissertation quantify the effect that increased temperature has on oyster shell growth and metabolism, drill feeding, and oyster inducible defenses. I found that oysters produced thicker shells at experimentally and latitudinally warmer temperatures, and that oyster drills consumed 60% more oysters with just a 4°C increase in seawater temperature above ambient conditions. Interspecific competition was assessed using marine epibenthic fouling communities, which are dominated by invasive species. Species’ growth responses to warmer temperature were positive in the northern portions of their latitudinal ranges and negative near the southern limits of their distributions, and I linked this thermal response to competitive outcomes. I also quantified the spread of invasive fouling species and found both summer temperature and commercial shipping to play a large role in the number of invasive fouling species in studied regions along both coasts of North America.

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