The combined effect of Macondo oil and corexit on sheepshead minnow (Cyprinodon variegatus) during early development

Abstract

During the 2010 Deepwater Horizon (DWH), oil spill an estimated 800 million L oil and 7.9 million L dispersant entered the environment. The potential adverse effects of the oil-dispersant mixture are poorly understood. The aim of this study was to investigate the impacts of this mixture on early development of sheepshead minnow (Cyprinodon variegatus), a small-bodied estuarine fish commonly found in the area affected by the DWH spill. Embryos were exposed to a chemically enhanced water accommodated fraction (CEWAF; 10:1 mixture of Macondo oil; Corexit 9500) for 48 hr, after which organisms were maintained in uncontaminated water for an additional 8 days. Impacts were assessed on embryonic (heart rate, development of eye pigmentation, embryonic movement measured) and larval (time to hatch, larval survival, standard length, and cyp1a gene expression) development. No significant alterations were found in survival, time to hatch or cyp1a at the end of the experiment. However, CEWAF induced significant decreases in heart rate of embryos, delayed development of eye pigmentation, reduced embryonic movement, and diminished standard length. These results indicate potential sublethal adverse consequences attributed to CEWAF exposure during early development, even in the absence of maintained cyp1a induction or survival rate, potentially affecting the fitness of organisms later in life.

Transgenerational effects of polycyclic aromatic hydrocarbon exposure on sheepshead minnows (Cyprinodon variegatus)

“…Embryonic cardiac effects resulting from hydrocarbon exposure, as demonstrated in the F 1 embryos from sheepshead minnow exposed to low HEWAF in the present study, is a well‐established phenomenon in fish. It has been demonstrated that PAHs can cause altered cardiac functioning directly, in PAH‐exposed embryos (Incardona et al , , ; Bosker et al ), and indirectly, in embryos collected from PAH‐exposed parental fish (Corrales et al ; Perrichon et al ).…”