Stimulate microbial breakdown of oil
Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
Background information and definitions
Oil spills can damage vegetation in marshes and swamps. Lighter oils can kill plants through their toxic effects, whilst heavier oils coat and smother vegetation (Michel & Rutherford 2013). Coastal salt marshes and mangroves are vulnerable to offshore tanker spillages. An estimated 5.5 million tonnes of oil has been released into mangrove-lined coastal waters around the world since 1958, killing at least 126,000 ha of mangrove vegetation (Duke 2016). Oil pipelines crossing inland marshes or swamps (e.g. the Russia-China Oil Pipeline; Yu et al. 2010) pose a threat from leaks and malfunctions. Loss of vegetation can increase the risk of erosion and permanent habitat loss (Beland et al. 2017; https://youtu.be/UkATPicHIo4).
This action includes various specific techniques for bioremediation, such as introducing oil-degrading microbes, tillage or aeration to increase the amount of oxygen available to microbes in sediments, and/or fertilization to provide nutrients for microbes. For more information about implementing these techniques, see practical manuals such as ExxonMobil (2008), Michel & Rutherford (2013) and Hoff & Michel (2014). The effectiveness of interventions may depend on the type of oil, exposure to waves and currents, climate, time of year that the spill occurred, and the species involved (Michel & Rutherford 2014). Caution: Interventions such as tillage or aeration can cause damage to wetland soils (Michel & Rutherford 2013).
Related actions: Use artificial barriers to block pollution; Introduce plants to marshes or swamps to control pollution; Physically or chemically remove oil; Cut or burn oil-contaminated vegetation (freshwater marshes – brackish/salt marshes – freshwater swamps – brackish/saline swamps).
Beland M., Biggs T.W., Roberts D.A., Peterson S.H., Kokaly R.F. & Piazza S. (2017) Oiling accelerates loss of salt marshes, southeastern Louisiana. PLoS ONE, 12, e0181197.
ExxonMobil (2008) Oil Spill Response Field Manual. ExxonMobil, USA.
Hoff R, & Michel J. (2014) Oil Spills in Mangroves: Planning & Response Considerations. US Department of Commerce.
Michel J. & Rutherford N. (2013) Oil Spills in Marshes: Planning & Response Considerations. US Department of Commerce.
Michel J. & Rutherford N. (2014) Impacts, recovery rates and treatment options for spilled oil in marshes. Marine Pollution Bulletin, 82, 19–25.