Publication Date

2012

Document Type

Honors Thesis

Department

Biological Sciences

Keywords

Zebra danio-Effect of oil spills on, Zebra danio-Embryos-Effect of water quality on, Polycyclic aromatic hydrocarbons-Physiological effect, Oil spils and wildlife, Neural crest, Zebrafish, Oil, PAH, Development, Deep horizon, Cardiovascular, Muscle

Abstract

On April 20th 2010, the Deepwater Horizon oil platform sank to a depth of 5000 ft., spilling approximately 4.93 million barrels of oil into the Gulf and making it the largest spill in history. Even though the oil stopped flowing, concerns were raised about the effects of crude oil on the marine flora and fauna in the Gulf. In addition, little is known about the toxicity of the two surfactants used to disperse the oil, Corexit 9500 and 9257, on the vulnerable process of development. Since utilizing native species is difficult due to lack of availability, genetic variation between individuals, and specialized care, this raises the necessity for an organism to model the effects of these compounds on embryonic development. Since development is conserved across species, the Zebrafish (Danio rerio), with its ease of maintenance, large clutch size, and completely sequenced genome is well suited to model the teratogenic effects of toxins. In addition, environmental pollutants appear in higher concentrations in animal tissue compared to the surrounding water, which makes the Zebrafish an ideal sentinel species. I investigated the effects of the water accumulated fraction (WAF) of Deepwater horizon (DWH) crude oil on the development of the zebrafish embryo, and found several defects in treated embryos which had been previously been seen. These were cardiovascular and craniofacial deformities, which we postulate could be the result of impaired cranial neural crest cell development. In addition, we also discovered a novel locomotor phenotype, perhaps as a result of observed deformities in slow muscle, as well as a reduction in the sensory axons of the peripheral nervous system and oligodendrocytes of the central nervous system. When treated with dispersants at varying concentrations, Iobserved that embryos exhibited dose dependent mortality rates, delayed development, and cell death. Thus, our research supports and expands upon what is known about the effect of crude oil and dispersants on the developing embryo, and allows us to model what might have happened and will happen to native fish species in the Gulf.

Language

English

Comments

107 p. : col. ill. Honors project-Smith College, Northampton, Mass., 2012. Includes bibliographical references (p. 94-107)

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