As oil spills into saltwater it will float on the surface, spreading rapidly into what is referred to as an oil slick.  When it becomes a very thin layer, with an iridescent rainbow appearance, it is called oil sheen. Waves may emulsify some oil into a "pudding" or "mousse" conisistency. As this thicker and stickier material continues to be broken down or "weathered", smaller tar balls are formed. Tar balls are very persistent, may travel long distances from the spill, and while often crusty on the outside are soft and sticky inside when stepped on.

Variations in the type of oil, the location of the spill, and the weather conditions present will determine what cleanup techniques are employed.  A boom is a floating barrier usually made of inflatable neoprene tubes or solid buoyant material, designed to contain the oil.  Most booms sit on the water surface, extending about a meter high. Other booms are flush with the top of the water and for deep water areas they will have a long skirt attached that hangs in the water column.  Once oil is contained within the boom, a skimmer floats on top of the oil slick and can suck or scoop up the oil and deposit into storage tanks.  These methods are most effective in calm weather conditions. 

Another common method is to speed up the biodegradation of the oil by introducing chemical dispersants or biological agents.  These allow for the oil to mix with water, creating tiny droplets that can easily be evaporated or broken down by natural bacteria.  A newer method of clean up is the use of in-situ burning, which is applying a controlled burn on newly spilled oil floating on the water surface.  These will only be done in when weather and water conditions are acceptable and operation will be terminated as soon as any danger from smoke or change in conditions arises.  If the oil makes it to the shoreline cleanup efforts may use high and low pressure hoses, vacuum trucks, shovels and road equipment.  The amount and intensity of the shoreline cleanup efforts will depend on the conditions of the individual sites and the sensitivity of the ecosystem. 

This information was compiled from the NOAA Office of Response and Restoration and University of Delaware Sea Grant Program to introduce readers to common oil spill terms and response methods.  For daily updates on the cleanup go to http://response.restoration.noaa.gov and click on current news.