Meeting Abstract
36.2 Sunday, Jan. 5 08:15 Effects of Corexit 9500A on gill structure and oxygen consumption in Danio rerio MOORE, S. L.*; OLIVA, O. M.; WILLIAMS, M. B.; POWELL, M. L.; MEADE, M. E.; ANTONY, V. B.; WATTS, S. A.; Univ. of Alabama, Birmingham; Univ. of Alabama, Birmingham; Univ. of Alabama, Birmingham; Univ. of Alabama, Birmingham; Jacksonville State Univ, Jacksonville, AL; Univ. of Alabama, Birmingham; Univ. of Alabama, Birmingham susan11@uab.edu
The oil dispersant Corexit 9500A was used during the Deepwater Horizon oil spill of 2010 in the Gulf of Mexico. Corexit is used to reduce oil into smaller bio-degradable droplets, facilitate oil degradation, and minimize biological impacts of oil rafts. Aerosol and liquid delivery of Corexit could expose organisms directly to high concentrations for short periods of time. To determine the direct effects of Corexit 9500A on aquatic organisms, zebrafish (Danio rerio) were exposed to a 400 ppm solution of Corexit for 24 hr (LC50 of 460 ppm). Gill tissue sections showed extensive edema and damage to the epithelial border of secondary lamellae. This damage increased as gills were exposed for 56 hr. Using immunohistochemistry, gill tissues stained strongly positive for heme oxygenase 1 (HO-1), suggesting a response to acute oxidative stress. Using 2′,7′-dichlorofluorescein dye, formation of reactive oxygen species was also found in gill tissue exposed to a 400 ppm solution of Corexit for 30 minutes. Whole animal respirometry of adult male and female zebrafish indicated that oxygen consumption rates were not affected by exposure at normal incubation temperature (28 C). These data suggest that short-term structural damage induced by Corexit did not affect properties of oxygen uptake and/or transport. At elevated temperatures (32 C) oxygen consumption rates were significantly increased with Corexit exposure, suggesting that high temperature could exacerbate the negative effects of dispersant. Furthermore, these data can be used to support new recommendations for dispersant usage in future spills.
