Depletion and biodegradation of hydrocarbons in dispersions and emulsions of the Macondo 252 oil generated in an oil-on-seawater mesocosm flume basin

• Published in: Marine pollution bulletin Vol. 84; no. 1-2; pp. 125 - 134
• Main Authors: Brakstad, Odd G., Daling, Per S., Faksness, Liv-G., Almås, Inger K., Vang, Siv-H., Syslak, Line, Leirvik, Frode
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.07.2014; Elsevier
• Subjects: Alkanes - metabolism; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Bacteria; Bacteria - genetics; Bacteria - metabolism; Basins; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Depletion; Dispersions; Droplets; Ecotoxicology, biological effects of pollution; Emulsions; Emulsions - chemistry; Flume basin; Flumes; Fundamental and applied biological sciences. Psychology; Hydrocarbons; Hydrocarbons - chemistry; Hydrocarbons - metabolism; Marine; Marine and brackish environment; Oil dispersions; Petroleum - analysis; Sea water ecosystems; Seawater - chemistry; Synecology; Biodegradation; Hydrocarbons; Oil dispersions; Emulsions; Depletion; Flume basin; Mesocosm; Hydrocarbon; Dispersion; Marine environment; Emulsion; Flumes; Organic compounds; Seawater
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2014.05.027

•Faster n-alkane degradation in chemically than physically prepared oil dispersions.•n-Alkane biodegradation supported by increase in alkB-containing bacteria.•Slower PAH than n-alkane biodegradation in the dispersions.•PAH biodegradation in chemically and physically prepared oil dispersions comparable.•Negligible biodegradation of n-alkanes and PAH in surface emulsions. Physically and chemically (Corexit 9500) generated Macondo 252 oil dispersions, or emulsions (no Corexit), were prepared in an oil-on-seawater mesocosm flume basin at 30–32°C, and studies of oil compound depletion performed for up to 15days. The use of Corexit 9500 resulted in smaller median droplet size than in a physically generated dispersion. Rapid evaporation of low boiling point oil compounds (C⩽15) appeared in all the experiments. Biodegradation appeared to be an important depletion process for compounds with higher boiling points in the dispersions, but was negligible in the surface emulsions. While n-alkane biodegradation was faster in chemically than in physically dispersed oil no such differences were determined for 3- and 4-ring PAH compounds. In the oil dispersions prepared by Corexit 9500, increased cell concentrations, reduction in bacterial diversity, and a temporary abundance of bacteria containing an alkB gene were associated with oil biodegradation.