Abstract:
The interactive effects of weathered oil and dispersant on the embryogenesis of the Gulf killifish were tested using laboratory mesocosms that were constructed using water spiked with oil, dispersant, or in combination. Treatment waters were generated at nominal salinities of 12 and 18 g/L. Control water was left undisturbed. Dispersant water was mixed at 22 mL of Corexit 9500 dispersant to 80 L of treatment water. Oil water was initially mixed at an approximate 1:4 oil:water ratio by volume and the dispersant was used at a 10:1 oil:dispersant ratio to generate oil/dispersant water. Treatment waters at the previously mentioned nominal salinities were weathered for 1, 4, and 16 weeks in treatment mesocosms. Embryos were monitored for hatch percent, mortality, and embryonic heart rate. Images of embryos were taken at hatch to screen for the presence of developmental abnormalities.
Data Parameters and Units:
2013-12-19_Exposed Fgrandis Embryo-CAB.xlsx-- NOTE: description of the laboratory mesocosms. Hatch and Mortality Summary: Salinity (12, 18 ppt), Treatment (Control, Oil, Dispersant, Oil/Dispersant), Weathering Time (week), Sample Size (count), % Hatch, Hatch (count), % Mortality, Mortality (count), % Live (but unhatched). Hatch and Mortality 12 ppt: Treatment (Control, Oil, Dispersant, Oil/Dispersant), Weathering Time (week), Days Post Fertilization, Daily Mortality (count), Cumulative Mortality (count), Daily Hatch (count), Cumulative Hatch (count). Hatch and Mortality 18 ppt: Salinity (18 ppt), Treatment (Control, Oil, Dispersant, Oil/Dispersant), Weathering Time (week), Days Post Fertilization (days), Daily Mortality (count) Cumulative Mortality (count), Daily Hatch (count), Cumulative Hatch (count). Heart Rate Data: Salinity (12, 18 ppt), Weathering Time (week), Fish Number (1-15), Replicate (NA Not Any, A, B, C, D), Treatment (Control, Oil, Dispersant, Oil/Dispersant in ppt). Picture Inventory: Salinity (18 ppt), Treatment Medium (Aquatic), Treatment (Oil/Dispersant), Weathering Time (week), Replicate (A, B, C, D), Fertilization Day (YYYY-MM-DD), Hatch Day (YYYY-MM-DD), Days to Hatch (days), Fish Number (count 1-5), Images of Exposed Fgrandis Embryos-- photographs with xml files.
Methods:
Embryos were derived from a common stock population from Cocodrie, LA. Embryos were obtained via in vitro fertilization on the following dates: 12 ppt 1 week weathered waters: 2012-06-20; 4 and 16 Week weathered waters: 201-07-17. 18 ppt 1, 4, and 16 week weathered waters 2013-07-09. Heart rate determined at 7 days post fertilization in the 12 ppt (n=15) and 18 ppt (n=12) salinity trials. Experiments were concluded after 21 days post fertilization. Percent live (but unhatched) represents the precentage of animals that were still alive by the conclusion of the study but had not yet hatched.
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