Sensitivity of eastern oyster (Crassostrea virginica) spermatozoa and oocytes to dispersed oil: Cellular responses and impacts on fertilization and embryogenesis. (June 2017)

• Record Type: Journal Article
• Authors: Vignier, J.; Volety, A.K.; Rolton, A.; Le Goïc, N.; Chu, F.-L.E.; Robert, R.; Soudant, P.
• Is Part Of: Environmental pollution. Volume 225(2017)
• Page Start: 270
• Page End: 282
• Publication Date: 2017-06
• Subjects: Deepwater Horizon oil spill -- Oyster -- Spermatozoa -- Oocyte -- Flow-cytometry; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2016.11.052
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The 2010 Deepwater Horizon (DWH) oil spill released millions of barrels of oil and dispersant into the Gulf of Mexico. The timing of the spill coincided with the spawning season of Crassostrea virginica . Consequently, gametes released in the water were likely exposed to oil and dispersant. This study aimed to (i) evaluate the cellular effects of acute exposure of spermatozoa and oocytes to surface slick oil, dispersed mechanically (HEWAF) and chemically (CEWAF), using flow-cytometric (FCM) analyses, and (ii) determine whether the observed cellular effects relate to impairments of fertilization and embryogenesis of gametes exposed to the same concentrations of CEWAF and HEWAF. Following a 30-min exposure, the number of spermatozoa and their viability were reduced due to a physical action of oil droplets (HEWAF) and a toxic action of CEWAF respectively. Additionally, reactive oxygen species (ROS) production in exposed oocytes tended to increase with increasing oil concentrations suggesting that exposure to dispersed oil resulted in an oxidative stress. The decrease in fertilization success (1-h), larval survival (24-h) and increase in abnormalities (6-h and 24-h) may be partly related to altered cellular characteristics. FCM assays are a good predictor of sublethal effects especially on fertilization success. These data suggest that oil/dispersant are cytotoxic to gametes, which may affect negatively the reproduction success and early development of oysters. Graphical abstract: Highlights: Deepwater Horizon oil spill coincided with the reproductive season of oysters. Crassostrea virginica spermatozoa and oocytes were exposed acutely to dispersed oil. Effects on early life stages were evaluated using FCM analysis and static bioassays. Toxic effects of oil/dispersant may be related to altered cellular characteristics. FCM assays are a good predictor of sublethal effects on fertilization success. Abstract : Using a cellular approach (i.e. flow-cytometry) coupled with standard bioassays, we demonstrated that oil-derived PAHs as well as physical properties of oil (i.e. droplets aggregation) and characteristics of the dispersant Corexit 9500A could impair spermatozoa and oocyte cellular functions, resulting in inhibited fertilization and depressed performance of embryo and larvae.