Date of Award

Summer 2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Health Sciences

First Advisor

Maria S. Sepulveda

Committee Chair

Maria S. Sepulveda

Committee Member 1

Cecon Mahapatra

Committee Member 2

Tomas Hook

Abstract

The 2010 Deepwater Horizon oil spill resulted in the release of ~ 5 million barrels of crude oil from the Macondo wellhead into the Gulf of Mexico. Oil from the spill was documented on 1,772km of shoreline with 847km of shoreline remaining oiled a year after the spill, and 687km of shoreline remaining oiled two years after the spill. Currently, there are few data available concerning long-term, sublethal effects associated with chronic exposure to crude oil in the Gulf of Mexico. In addition to the anthropogenic-induced stress of polycyclic aromatic hydrocarbon (PAH) exposure, aquatic organisms living in estuarial areas of the Gulf of Mexico must also contend with environmental stressors including large fluctuations in dissolved oxygen (DO), temperature, and salinity. For this study, Fundulus grandis was chosen as a model species to investigate the combined effects of oil contaminants (PAHs) and environmental stressors. Embryos <24hpf were exposed to various PAH concentrations and environmental conditions>(DO: 2, 6ppm; temperature: 20, 25, 30°C; salinity: 3, 7, 30ppt) until hatching and concentrations eliciting 50% mortality (LC50) calculated. Regardless of environmental conditions, LC50 values fell within a narrow range (43.2–77.2ppb), with the exception of one experiment conducted at high DO (6ppm), low temperature (20°C) and high salinity (30ppt) resulting in an LC50 value of 357.1ppb. The data suggest that low temperatures and high salinities, such as may be present in estuarial waters of the Gulf of Mexico, may significantly reduce sensitivity to PAH exposure during early life stage development. The results of this study may be used to construct population models for Fundulus grandis based on environmental conditions and oiling known to exist in the Gulf of Mexico.

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