Sensitivity of eastern oyster (Crassostrea virginica) spermatozoa and oocytes to dispersed oil: Cellular responses and impacts on fertilization and embryogenesis.
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.
Department of Marine and Ecological Sciences, College of Arts and Sciences, Florida Gulf Coast University, Fort Myers, FL 33965, USA; Laboratoire des Sciences de l'Environnement Marin (UMR 6539-LEMAR), IUEM-UBO, Technopole Brest Iroise, 29280 Plouzané, France.
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Vignier
Department of Marine and Ecological Sciences, College of Arts and Sciences, Florida Gulf Coast University, Fort Myers, FL 33965, USA. Electronic address: voletya@uncw.edu.
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Volety
Department of Marine and Ecological Sciences, College of Arts and Sciences, Florida Gulf Coast University, Fort Myers, FL 33965, USA; Laboratoire des Sciences de l'Environnement Marin (UMR 6539-LEMAR), IUEM-UBO, Technopole Brest Iroise, 29280 Plouzané, France.
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Rolton
Laboratoire des Sciences de l'Environnement Marin (UMR 6539-LEMAR), IUEM-UBO, Technopole Brest Iroise, 29280 Plouzané, France.
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Le Goïc
Virginia Institute of Marine Science (VIMS), College of William and Mary, Department of Aquatic Health Sciences, Gloucester Point, 23062 VA, USA.
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Chu
Ifremer, Unité Littoral, Centre Bretagne - ZI de la Pointe du Diable, CS 10070, 29280 Plouzané, France.
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Robert
Laboratoire des Sciences de l'Environnement Marin (UMR 6539-LEMAR), IUEM-UBO, Technopole Brest Iroise, 29280 Plouzané, France.
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Soudant
D000818:Animals; D049896:Crassostrea / Q000502:physiology*; D047108:Embryonic Development / Q000187:drug effects*; D007814:Larva / Q000187:drug effects; D008297:Male; D008800:Mexico; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010578:Petroleum / Q000633:toxicity*; D059392:Petroleum Pollution; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D010578:Petroleum; D014874:Water Pollutants, Chemical
Deepwater Horizon oil spill; Flow-cytometry; Oocyte; Oyster; Spermatozoa