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Bioremediation of Oil Spills

Bioremediation is any process that uses decomposers and green plants, or their enzymes, to improve the condition of contaminated environments. Bacteria can be used to clean up oil spills in the ocean through bioremediation. Specific bacteria can be used to bioremediate specific contaminants, such as hydrocarbons, which are present in oil and gasoline.

Oil spills in the ocean have a severely negative effect on marine life, especially seabirds and filter-feeders. Seabirds, such as seagulls and ducks, spend most of their life on water and go to land only during their nesting period. The feathers of many seabirds are wettable and must be carefully preened (or dried) for flight. If feathers come into contact with oil, the seabird ingests the oil while trying to preen. Filter-feeders, such as clams and oysters, take in surface water through their gills and filter it to take out any microscopic food. If there is oil on the water, it gets concentrated within these shellfish and then accumulates in their predators in a higher concentration.

In this demonstration, soap is used to mimic the effect of bioremediation by bacteria by minimizing the area of the surface covered by oil. Oceanic oil spills are managed using containment methods that float on the water and bioremediation (adding bacteria to the oil to speed up the breakdown process).

Objectives

  • Outline the effect of oil spills and describe a simple bioremediation strategy.

Materials

  • Per Demo or Group:
    large glass bowl
    water
    vegetable oil
    cocoa powder
    3 feathers (preferably sea gull feathers)
    container of dishwashing soap labelled “ Fake bacterial solution”

Key Questions

  • How do oil spills harm the environment and seabirds?

What To Do

  1. Add water to the glass bowl.
  2. Have a student dip a feather into the water.
  3. Observe the feather. Is it wettable or does it stay dry?
  4. Have another student mix some cocoa powder and vegetable oil in a cup to make an oil slick. Gently pour the oil slick onto the surface of the water.
  5. Have a student dip a fresh feather into the slick.
  6. Observe the surface of the feather and compare it to the feather dipped in plain water. Discuss whether a sea bird could fly with oil-covered feathers.
  7. Add one or two drops of your bacterial solution (soap) to disperse the oil.
  8. Have a student dip a feather into the “bioremediated” water.
  9. Observe the surface of the feather and compare to the other feathers. Did the feather come out clean?

Extensions

  • Discover some methods we use to clean up large oil spills in freshwater and/or ocean systems.
  • Discuss the impact that contaminants in our waste water might have on our water ecosystems.