Abstract:

We conducted laboratory experiments to determine the effects of Corexit 9500 and dispersed crude oil on marine microzooplankton. We collected plankton samples in the field that were sieved and sorted to obtain individuals from 7 taxa that were then cultured in the lab for use in the study: Strombidum sp., Spirostrombidium sp., Eutintinnus pectinis, Favella ehrenbergii, Gyrodinium spirale, Protoperidinium divergens, Protoceratium sp. An additional species for use in this study, Oxyrrhis marina, was obtained from the University of Texas Culture Collection of Algae. 24 and 48 hour experiments were conducted exposing a single species to one of four conditions: control, crude oil emulsions, dispersant-treated crude oil emulsion, or a solution of dispersant alone in seawater. This dataset reports the cells counted for 2 –4 replicates of each species and treatment. Additionally, the EC50 is calculated for each species and treatment.

Suggested Citation:

Almeda, Rodrigo, et al. 2016. Corexit 9500A, the chemical dispersant used in the DWH oil spill, increases the toxicity of crude oil to marine microzooplankton. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7TT4NZ2

Publications:

Almeda, R., Hyatt, C., & Buskey, E. J. (2014). Toxicity of dispersant Corexit 9500A and crude oil to marine microzooplankton. Ecotoxicology and Environmental Safety, 106, 76–85. doi:10.1016/j.ecoenv.2014.04.028

Purpose:

To determine the acute toxicity of Corexit 9500A, and physically and chemically dispersed Louisiana light sweet crude oil to marine microzooplankton (oligotrich ciliates, tintinnids and heterotrophic dinoflagellates).

Data Parameters and Units:

Almeda et al. 2014_microzooplankton & oil publication_revised.xlsx-- EXPERIMENTS_CELL_COUNTING: species, incubation time (hours), treatment (listed below), cells counted, cell concentration (cells/mL), % growth of mortality, average growth or mortality, average growth or mortality (%), standard deviation (SD) EC50: species, sigmoid/logistic model (N= N0/ (l + (C/EC50)^b), N: cell concentration, N0: cell concentration in absence of crude oil or dispersant (crude oil or dispersant concentration = 0), C: crude oil/dispersant-treated crude oil/dispersant concentration (uL/L), EC50: median effect concentration (the pollutant concentration required to reduce the population by half compared to cell concentrations in the absence of pollutants, N0), b: slope factor, standard error, t-value, p-value, r^2 Treatments: control = absence of pollutants oil = suspensions of crude oil droplets in seawater dispersed physically oil+disp = dispersant-treated crude oil emulsions (crude oil emulsions in seawater dispersed physically and chemically) disp = a solution of dispersant alone in seawater A, B, C, and D are the different Replicates Concentrations of crude oil and dispersant used: E1 oil: crude oil concentration = 1 uL/L E1 disp: dispersant concentration = 0.05 uL/L E1 oil + disp: dispersant-treated crude oil = 1 uL/L of crude oil and 0.05 uL/L of dispersant E2 oil: crude oil concentration = 5 uL/L E2 disp: dispersant concentration = 0.25 uL/L E2 oil + disp: dispersant-treated crude oil = 5 uL/L of crude oil and 0.25 uL/L of dispersant E3 oil: crude oil concentration = 10 uL/L E3 disp: dispersant concentration = 0.50 uL/L E3 oil + disp: dispersant-treated crude oil = 10 uL/L of crude oil and 0.50 uL/L dispersant

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