Abstract:

Petrocarbon exposure studies were conducted on three isolated clones from coastal Alabama in the Gulf of Mexico including a diatom (Skeletonema spp.), a dinoflagellate (Prorocentrum spp.) and a chlorophyte (Tetraselmis spp.). Laboratory cultures were exposed to water accommodated fraction of crude oil (WAF), WAF that was chemically enhanced with dispersant (CEWAF), and negative control with just dispersant (Dispersant). Cellular concentrations and physiological response among treatments were measured for the duration of the exponential phase for each group relative to control treatments (no petrocarbon).

Suggested Citation:

Liesl Cole, Jason Latham, Jeffrey Krause, Kimberlee Thamatrakoln. 2019. Coastal Alabama phytoplankton resilience to petrocarbon loading. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-0tqq-0153

Purpose:

The goal was to examine changes in cell abundance with time in monocultures (individual isolates) and mixed (all three isolates) cultures in response to petrocarbon loading.

Data Parameters and Units:

Organism Genus; Experiment Date (YYYYMMDD); Days Since Start of Experiment; Treatment (Control, water accommodated fraction of crude oil (WAF), WAF that was chemically enhanced with dispersant (CEWAF), Dispersant); Treatment amount (ppm); Replicate (a, b, c, d, e, f); Abundance (cells per millilter (cells/mL)); Fm (maximum fluorescence, relative fluorescence units); Fv/Fm (maximum efficiency of photosystem II, dimensionless), treatment amount (parts per million (ppm), i.e. amount of loading).

Methods:

There are four experimental treatments- WAF, CEWAF, Control, and Dispersant which was a negative control. The concentration of treatment ranged from 1 to 40 ppm. Tetraselmis and Prorocentrum were grown in f/2 media (no Si) (Guillard and Ryther, 1962; Guillard, 1975). Skeletonema and Asterionellopsis were grown in f/2 plus Si media (Guillard and Ryther 1962, Guillard 1975). f/2 made by adding nutrients to autoclaved filtered seawater that has cooled. Media used for cultivation was the same media used for experiments. Cells were grown at 20 degrees Celsius, at a 12:12 light-dark cycle, at light irradiance of 100 uEinsteins/m2/s. Fluorescent Measurements were made with a mini-FIRe (Fluorescence Induction and Relaxation) fluorometer to obtain Fm and Fv/Fm. The instrument was custom built by Maxim Gorbunov at Rutgers and is based on the same principles as the previous FIRe instrument (Gorbunov and Falkowski, 2004). Cell Counting was by means of a BD Accuri C6 with C-Sampler Automatic Arm (Model Number: 4291). 150uL of each culture were plated in a clear 96-well plate. Using the software of the BD Accuri, each sample was analyzed for 1 minute on a setting of Medium (core size 16 um, Flow Rate 35 uL/min), washing the SIP between every sample, agitating the plate once every 4 wells. After sampling, data were plotted as log SSC-H (Side Scatter) (X-axis) vs. log FL3-H (Chlorophyll fluorescence) (Y-axis). Cells with high chlorophyll were gated as the live population.

Instruments:

Mini-FIRe (Fluorescence Induction and Relaxation) fluorometer. BD Accuri C6 with C-Sampler Automatic Arm (Model Number: 4291).

Provenance and Historical References:

Guillard, R. R. L., & Ryther, J. H. (1962). Studies of marine planktonic diatoms: I. Cyclotella nana Hustedt, and Detonula confervacea (Cleve) Gran. Canadian Journal of Microbiology, 8(2), 229–239. doi:10.1139/m62-029 Guillard, R. R. L. (1975). Culture of Phytoplankton for Feeding Marine Invertebrates. Culture of Marine Invertebrate Animals, 29–60. doi:10.1007/978-1-4615-8714-9_3 Gorbunov, M. Y., & Falkowski, P. G. (2004). Fluorescence induction and relaxation (FIRe) technique and instrumentation for monitoring photosynthetic processes and primary production in aquatic ecosystems. In Photosynthesis: Fundamental Aspects to Global Perspectives, Proc. 13th International Congress of Photosynthesis, Montreal, Aug (pp. 1029-1031).

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