Dataset Authors

Paul A. Montagna


This dataset contains deep-sea sediment Microtox toxicity data analyzed from sediment cores collected aboard R/V Ryan Chouest (10-07-10-RC, 2010-10-07 to 2010-10-17), R/V Ocean Veritas (09-24-2010_Ocean_Veritas, 2010-09-24 to 2010-10-23) and R/V Gyre (09-14-2010_Gyre, 2010-09-14 to 2010-10-20) cruises in the northern Gulf of Mexico from 2010-09-16 to 2010-10-23. Following the Deepwater Horizon oil spill, a series of cruises was undertaken to determine if oil reached the bottom and if sediment toxicity was occurring. Sampling occurred after the wellhead was capped from September through October 2010. Sediment sampling was performed using OSIL multiple corers at 179 stations at water depths ranging from 16 m to 2767 m. A sediment quality approach was used where chemical contaminants were measured to indicate a dose effect, and in situ bacterial toxicity to indicate a biological effect. Three sediment sub-cores were taken from one multi-corer core using a 10 cc (=10 ml) syringe from the undisturbed surface. The three sub-cores were composited into one 30 cc sediment sample for toxicity analysis. Some sediments were analyzed immediately on shipboard, but other sediments were preserved at 20 ºC and analyzed on-shore. Samples measured on shipboard were held at 4 ºC in the dark. The bacteria preparation is added to bulk sediment samples, mixed thoroughly, and then a dilution series is created, and the samples are exposed for 30 minutes. The bacteria and sediment are pelleted, and fluorescence measurements are taken to determine the concentration that provides an EC50 response. The dataset contains the depth, date and location of sampling collection stations, effect concentration 50 values, and the total concentration of polycyclic aromatic hydrocarbons (PAHs).


Supplemental Information

The worksheet "Data" contains - Station [station #]; SampleDate [Date sampled, DDMONYYYY], Latitude [decimal degrees], Longitude [decimal degrees], Depth [meter], EC50 [Effect Concentration 50 (mg/L)], PAH [Total Polycyclic Aromatic Hydrocarbons (ug/kg)]. The worksheet "RawData" contains - Ship [Ship name, vessel samples collected from; GY = R/V Gyre, OV = R/V Ocean Veritas, RC = R/V Ryan Chouest]; SampleID [Sample identification number with six words separated by a dash ("-") where 1=Matrix (Sediment) , 2=Date (ymd), 3=Ship, 4=Station, 5=analyte (microtox), and 6=sample sequence number]; SampleDate [Sample collection date, DD-Mon-YYYY]; AnalysisDate [sample analysis date, DD-Mon-YYYY]; Station [Station name]; EC50 [Effect Concentration 50 (mg/L) - Value required to elicit a negative 50% effect relative to a control sample]; CIL [Confidence interval, lower bound]; CIU [Confidence interval, upper bound]. Dataset also includes the cruise documentation for R/V Ryan Chouest (10-07-10-RC), R/V Ocean Veritas (09-24-2010_Ocean_Veritas) and R/V Gyre (09-14-2010_Gyre) cruises led by chief scientists Eric Houston, Frank Coluccio, and Abby Spencer respectively.|Details of the sediment sampling and chemical contaminant measurements are provided in Montagna et al., (2013). The chemical contaminant data was part of the initial Response assessment and is available in the Operational Science Advisory Team (2010, Toxicity was measured using the Microtox® system. Microtox uses the fluorescence of the bioluminescent bacterium, Vibrio fischeri NRRL B-11177, to assess the toxicity of samples. Reductions in bioluminescent activity indicate corresponding increases in toxicity (Montagna, P.A. and S.S. Arismendez., 2020, The bioluminescence of V. fischeri is sensitive to most toxicants; such as pesticides, phenolic compounds, and metals. The Microtox method yields result comparable to standard amphipod and urchin toxicity tests for water and sediment samples. Results are reported as effect concentration 50 (EC50) values (mg/L) required to elicit a negative 50% effect relative to a control sample. Therefore, low EC50 values denote a large toxic effect. It is much less labor-intensive than other amphipod or sea urchin exposure tests and utilizes bulk sediment rather than pore water or preservation of bulk sediment to expose animals in arrays of dilutions. PAH data are available through the DIVER (Data Integration Visualization Exploration and Reporting) website (|Microtox (TM) system.|||Operational Science Advisory Team (OSAT). 2010. Summary Report for the Sub-sea and Sub-Surface Oil and Dispersant Detection: Sampling and Monitoring. Montagna, P. A., Baguley, J. G., Cooksey, C., Hartwell, I., Hyde, L. J., Hyland, J. L., Kalke, R.D., Kracker, L.M., Reuscher, M. and Rhodes, A. C. E. 2013. Deep-Sea Benthic Footprint of the Deepwater Horizon Blowout. PLoS ONE, 8(8), e70540. doi:10.1371/journal.pone.0070540 Montagna, P.A. and S.S. Arismendez 2020. Crude Oil Pollution II. Effects of the Deepwater Horizon contamination on sediment toxicity in the Gulf of Mexico. In: D’Mello, J.P.F. (ed.), A Handbook of Environmental Toxicology: Human Disorders and Ecotoxicology, CAB International, Oxfordshire, U.K., pp. 311-319.


Determine if sediment toxicity occurred in the deep sea after the Deepwater Horizon blowout and oil spill.


Deep sea, Sediment, Toxicity, Microtox, Aliivibrio fischeri, PAHPolycyclic aromatic hydrocarbon (PAH)




April 2020

Point of Contact


Paul A. Montagna


Texas A&M University-Corpus Christi / The Harte Research Institute for Gulf of Mexico Studies


Melissa Rohal Lupher


Texas Water Development Board

Funding Source




Rights Information

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This work is licensed under a Creative Commons Public Domain Dedication 1.0 License.