Abstract:

This study involved a 7 day land-based mesocosm experiment within 120 gallon tanks placed in a temperature controlled water bath. The mesocosm set up is located at UTMSI, Port Aransas, Texas. Natural seawater was pumped from the shipping channel into each tank during an incoming tide to obtain natural plankton communities. Each tank had a gentle aeration system installed to provide mixing and ensure oxygenation levels remain consistent. This experiment was carried out between June 9th and 16th, 2016 to investigate the impact of 5ppm and 10ppm chemically dispersed crude oil on natural Protozoan populations. Both treatments plus a control were tested in triplicate tanks. Louisiana light sweet crude oil was dispersed using Corexit 9500A, with a dispersant to oil ratio of 1:20, and added to the corresponding treatment tanks to make the final crude oil concentrations of 5ppm and 10ppm. Samples were collected every 24hrs to analyze protozoan community alterations. Both live and preserved samples were analyzed via microscopy methods and Flow imaging cytometry. This allowed for the examination of daily survival, mortality and potential recovery rates of protozoan species exposed to two concentrations of chemically dispersed oil within conditions which best reflect ambient environmental conditions.

Suggested Citation:

Sarah Cosgrove, Edward Buskey, Maud Moison, Tatiana Severin. 2017. Community analysis of planktonic protozoa following exposure to chemically dispersed crude oil. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7CN72BB

Purpose:

This data set represents the densities (per 50 ml) of over 42 genera of marine protozoa. The purpose of these densities is to analyse community structural changes in a short-term mesocosm set-up following exposure to two concentrations of chemically dispersed crude oil (5 and 10ppm). The data set also includes additional measured parameters including temperature, salinity, chlorophyll and fluorometry (UV measurements of relative oil levels).

Data Parameters and Units:

Trial, Date (MM/DD/YYYY), Concentration (ppm), Species name, Species density (total in a 50 mL sample), Tank number, Time (GMT), Temperature (deg C), Salinity (ppt), Chlorophyll size fraction (um), Chlorophyll (ug/L), Fluorometer UV readings (raw fluorescence units) Treatments: DO = Dispersed Oil (ratio of 1:20 Corexit 9500A to Sweet Louisiana crude oil) Diatom diversity x= presence d= dominating All species counts represent the total number in a 50 ml sample.

Methods:

Species counts were carried out via microscopy using the Utermohl settling method. Each count is representing 50 ml settled.

Instruments:

Temperature was logged using a HOBO Temperature logger Salinity was measured using a temperature/salinity probe Both chlorophyll and oil levels were measured using a trilogy fluorometer

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