Abstract:

Mesocosm experiments were performed as part of the ADDOMEx GOMRI funded program with seawater collected from the NGOM and “seeded” with microbial populations collected from coastal Texas (in Galveston Bay) in October of 2015. At the end of these experiments, exopolymeric substances (EPS) were isolated from water sampled from particles that sank to the bottom of each tank throughout the course of the experiment. The operationally-defined EPS were freeze-dried, and the freeze-dried solid material was subjected to solid-state 13C NMR spectroscopic analysis before and after dichloromethane extraction. The data contained in this dataset represents the raw chemical shift and intensity data obtained directly from the instrument.

Suggested Citation:

Pat Hatcher and Andrew Wozniak. 2017. Response of oil-degrading microbes in a ternary system (oil-dispersant-EPS): COAST, coastal water mesocosm with microbial concentrate, solid-state 13C NMR data. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N70R9MFP

Publications:

Hatcher, P. G., Obeid, W., Wozniak, A. S., Xu, C., Zhang, S., Santschi, P. H., & Quigg, A. (2018). Identifying oil/marine snow associations in mesocosm simulations of the Deepwater Horizon oil spill event using solid-state 13 C NMR spectroscopy. Marine Pollution Bulletin, 126, 159–165. doi:10.1016/j.marpolbul.2017.11.004

Purpose:

To investigate molecular level differences in natural EPS, EPS impacted by oil, and EPS impacted by oil and dispersant mixtures.

Data Parameters and Units:

File names correspond to the treatment (CEWAF, DCEWAF, WAF, or control) and processing state (before or after dichloromethane) Spectral Intensity = the spectral response (arbitrary units) at the given chemical shift Chemical Shift = parts per million

Methods:

The seawater was collected from the same location as that used in TeCOAST Mesocsom, but on October 17 2015, from 8 kilometers off shore south of Galveston (TX) in the Gulf of Mexico. The salinity was 31. The seawater was processed through a charcoal filter to remove large particles and debris. Four treatments were prepared in triplicate. Control tanks were filled with seawater and a plankton mixture. Water accommodated fraction (WAF) of oil was prepared by mixing 25 mL (5 ml ~ every 30 min for 2.5 hrs) of Macondo surrogate oil into 130 L of seawater then mixing for 12 to 24 hrs (Knap et al. 1986; Knap et al. 2016 in preparation). The WAF was then introduced into the WAF mesocosm tanks and filled to 87 L and mixed. From these WAF tanks 6 L was removed for other experiments and analyses (2L for roller tables, 2 L dark/light, 4 L hydrocarbon analyses). In order to make chemically enhanced water accommodated fraction (CEWAF), Corexit was mixed with oil in a ratio of 1:20 and 25 mL of this mixture (5 ml every 30 min for 2.5 hrs) of surrogate oil plus Corexit was added to 130 L of seawater which was mixed for 8 to 24 hrs prior to being transferred to the mesocosm tanks. The CEWAF was then introduced into the CEWAF mesocosm tanks and filled to 96 L and mixed. From these CEWAF tanks 15 L was removed for other experiments and analyses (9 L for the DCEWAF mesocosms, 2L for roller tables, 2 L dark/light, 4 L hydrocarbon analyses). Diluted CEWAF (DCEWAF) was prepared by mixing 9 L of CEWAF with 78 L of the original seawater for a total volume of 87 L. From these DCEWAF tanks 6 L was removed for other experiments and analyses (2L for roller tables, 2 L dark/light, 4 L hydrocarbon analyses). Plankton (≥63 µm) were collected using a net and transferred into polycarbonate bottles. This concentrated plankton mass was introduced to the tanks and stirred (2 L to each final volume 83 L) immediately prior to starting the experiments. The EOE mean concentration of the three mesocosms for the control, WAF, DCEWAF and CEWAF at the start of the experiments were 0 mg/L, 0.26 mg/L, 2.74 mg/L and 41.5 mg/L, respectively. The EOE mean concentration of the three for the control, WAF, DCEWAF and CEWAF mesocosms after 72 hours were 0 mg/L, 0.06 mg/L, 1.03, and 17.3 mg/L, respectively. Estimated Oil Equivalence (EOE) The estimated oil equivalents (EOE) were determined by fluorescence (Wade et al. 2011) using Macondo surrogate oil as a standard to produce calibration curves at 5 to 7 concentrations. Water samples (5 to 20 ml) were extracted with 5 ml of dichloromethane. An aliquot of the extract was placed in a cuvette for fluorescence analyses (Horiba Scientific Aqualog Fluorometer). The EOE were determined from the calibration curve (Wade et al. 2011). Samples with florescence responses that exceeded the calibration curve were diluted so that their florescence was within the calibration range. Samples were taken at the beginning and end of the experiment and at intervals in between and at the same time point as measurements of other parameters during the experiment. EOE data can be found in GRIIDC dataset UDI: R4.x263.000:0019.

Instruments:

Avance II 400 MHz nuclear magnetic resonance spectroscope

Individual Files: