Biodegradation of dispersed Macondo oil in seawater at low temperature and different oil droplet sizes. Issue 1 (15th April 2015)

• Record Type: Journal Article
• Authors: Brakstad, Odd G.; Nordtug, Trond; Throne-Holst, Mimmi
• Is Part Of: Marine pollution bulletin. Volume 93:Issue 1/2(2015:Apr.)
• Page Start: 144
• Page End: 152
• Publication Date: 2015-04-15
• Subjects: Oil -- Biodegradation -- Dispersions -- Seawater -- Low temperature -- Droplet size; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2015.02.006
• Languages: English
• ISSNs: 0025-326X

Abstract

Graphical abstract: Highlights: A novel oil droplet system was used for biodegradation studies of dispersed oil. Biodegradation was compared in dispersions with 10 and 30 μm droplet sizes. Oil droplet size distributions maintained in sterilized, but not in normal seawater. Biodegradation of hydrocarbons was faster in 10 than in 30 μm droplet dispersions. Dispersant treatment to reduce oil droplet size may increase biodegradation rates in deepwater oil droplets. Abstract: During the Deepwater Horizon (DWH) accident in 2010 a dispersant (Corexit 9500) was applied at the wellhead to disperse the Macondo oil and reduce the formation of surface slicks. A subsurface plume of small oil droplets was generated near the leaking well at 900–1300 m depth. A novel laboratory system was established to investigate biodegradation of small droplet oil dispersions (10 μm or 30 μm droplet sizes) of the Macondo oil premixed with Corexit 9500, using coastal Norwegian seawater at a temperature similar to the DWH plume (4–5 °C). Biotransformation of volatile and semivolatile hydrocarbons and oil compound groups was generally faster in the 10 μm than in the 30 μm dispersions, showing the importance of oil droplet size for biodegradation. These data therefore indicated that dispersant treatment to reduce the oil droplet size may increase the biodegradation rates of oil compounds in the deepwater oil droplets.