Abstract:

This dataset covers part of the data for experiments in which oil was added to the sediment surface in mesocosms. Data provided here are experimental design, bioturbator data (including survival/recovery), environmental data (D.O., redox, turbidity, etc.) for sediment and water in the mesocosms, and data on microbial naphthalene-degradation capacity in the mesocosm sediment. Data on PAH levels in water and sediment and genomics data on microbial community composition will be provided in separate datasets (respectively R2.x226.000:005 and R2.x226.000:002).

Suggested Citation:

Klerks, Paul, and Nihar Deb Adhikary. 2015. Mesocosm experiments with oil at sediment surface - experimental design, environmental data, bioturbator data, PAH degradation capacity. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7GT5K6N

Publications:

Klerks, P. L., Kascak, A., Cazan, A. M., Deb Adhikary, N., Chistoserdov, A., Shaik, A., … Louka, F. R. (2018). Effects of the Razor Clam Tagelus plebeius on the Fate of Petroleum Hydrocarbons: A Mesocosm Experiment. Archives of Environmental Contamination and Toxicology, 75(2), 306–315. doi:10.1007/s00244-018-0515-0

Purpose:

Experiment aimed at determining the effect of bioturbators on the distribution and degradation of petroleum hydrocarbons in nearshore environments. This specific dataset provides data on experimental design and bioturbator information (as background information), data on environmental variables measured in the mesocosms, and data on microbial naphthalene-degradation capacity in the mesocosm sediment. The environmental data are meant to provide insights on how the bioturbators may be affecting the distribution and biodegradation of the hydrocarbons.

Data Parameters and Units:

Experimental design worksheet includes details on when the experiment was conducted, when sampling was conducted (for environmental variables and petroleum hydrocarbons) and what tanks received which of 4 treatments (bioturbator present/absent * oil added or not). Bioturbator worksheet has info on bioturbator identity/source/experimental density, recap of treatment assignments to specific tanks, and listing of the number of bioturbators recovered at the end of the experiment. Turbidity worksheet has turbidity results (in NTU) by observation day and tank. Redox worksheet has redox measurement results (in mV), 3 replicate measurements and mean, by observation day and tank. D.O. worksheet has ODO measurement results (in % saturation and mg/L D.O.) and probe-adjusted data (since measurements were conducted with separate probes, in clean tanks and pyrene-dosed tanks, to avoid cross-contamination). The same worksheet has daily results from measurements on a single sample using both probes - for establishing a correction for minor differences between the two probes). ODO measurements are listed by observation day and tank. Temperature worksheet has measurements for water temperature (in *C; duplicate measurements and means), measurements for sediment temperature (in *C; duplicate measurements and means), the difference in temperature between water and sediment of the same tank (Delta T in °C), and the absolute temperature difference (Delta T abs in °C). Temperature data are listed by observation day and tank. The naphthalene degradation worksheet has 14C radioactivity data for the CO2 traps for traps removed from the respirometers at 0, 12, 24 and 48 hours during the incubation. Radioactivity data were converted from “cpm” (counts per minute) to “dpm” (disintegrations per minute), and (using the specific activity of the 14C naphthalene and the changes in radioactivity between the 0h and 12h time points (in the experiment with the clams) or the 0h and 12h time points (in the experiment with the ghost shrimp), to a degradation rate in expressed in nmoles/day/g sediment.

Methods:

Water samples of approximately 30 mL were collected from the tanks (at approximately mid-depth of the water column) using a turkey baster and placed in 30-mL glass tubes for transport to the lab. In the lab, water samples were transferred to glass tubes and turbidity quantified on a Hach 2100A turbidimeter, calibrated daily with GELEX® secondary turbidity standards. Turbidity was expressed in nephelometric turbidity units (NTU). Redox measurements were obtained with a custom made redox electrode with a platinum indicator electrode exposed at the end of a thin rigid shaft and a Corning calomel reference probe, using a portable pH/volt meter (Cole Parmer Digi-Sense® pH/mV/Temp). The bottom half of the reference electrode was placed in the water column, while the indicator electrode was pushed into the sediment such that its exposed platinum end was at mid-depth of the sediment. Mid-depth values were determined at 3 locations in each tank. Redox readings were allowed to stabilize (“stable” if no change within 5 seconds) prior to recording a redox value. Dissolved oxygen (D.O.) measurements were obtained with the YSI ProODO meter. Optical D.O. readings were taken at the middle of the water column depth in each tank, and D.O. recorded in “% saturation” and “mg/L O2”. Different probes were used for clean tanks and tanks to which petroleum hydrocarbons were added. The correct for differences between the probes, measurements were taken with both probes on a single water sample each day that water quality measurements were done. Probe-adjusted ODO values were calculated on the basis of the average differences between the two probes for these water samples. Temperature measurements were obtained with a Fisher Scientific NiCr/NiAl T/C type K probe (0.1 °C resolution) with the Traceable® type K meter. On each tank, two measurements were taken in the middle of the water column and two measurements were taken at mid-depth of the sediment. Different probes were used for clean tanks and those to which petroleum hydrocarbons were added. Since the goal was to quantify differences between the sediment and the water column within tanks (obtained with the same probe), no corrections were needed for between-probe differences. For quantifying the naphthalene degradation capacity, 14C naphthalene was used at a specific activity of 57 mCi/mmole. Sediment was removed from the mesocosms (a sediment slurry taken from the top 10 cm of the sediment) at the end of the mesocosm experiments and brought to the UL Lafayette Biology department’s radionuclide laboratory. Wide mouth glass jars (Fisher Scientific) (130-mL capacity) with tightly-closing septa-lids were used as respirometers. The septa lids allowed adding the radiolabeled substrate and other reagents into the closed jars using a microsyringe. Glass scintillation vials, each with 5 ml of 2M NaOH, were used as CO2 traps. The principle of our methodology is that the microbial degradation of 14C-naphthalene results in the production of 14CO2, which will react with the NaOH in the trap and produce Na214CO3. The latter is then quantified using scintillation counting. A 20-g aliquot of sediment was placed in each jar, in which then a CO2-trap was place! d, and the lid tightened. This was done for 12 replicates per mesocosm tank (3 replicates each for 4 different time points). At the end of each specific incubation period, 3 ml of acetic acid was added to each of the respirometers for that time period in order to stop the 14C-naphthalene-degradation. The traps were removed from the respirometers, the outside of the trap was thoroughly cleaned, scintillation cocktail (ScintiVerse™ E Cocktail; Fisher Scientific) was added, and radioactivity quantified in a scintillation counter (Packard Tri-carb 1900CA). Since raw results showed that most of the 14C-naphthalene degradation took place early on, the 0 and 12 hour data (for the razor clam experiment) or the 0 and 8 hour data (for the ghost shrimp experiment) were used to quantify the microbial naphthalene-degradation capacity in the sediment.

Instruments:

Instrumentation information is provided in the methods section.

Error Analysis:

Instruments were calibrated prior to use. Data entry into digital files was duplicated.

Provenance and Historical References:

Dataset R2.x226.000:0005 will contain the results from the hydrocarbon analyses of the sediment and water samples from these experiments. Dataset R2.x226.000:0002 will contain the results from the microbial genomics analyses.

Individual Files: