Wednesday, April 28, 2010

When the Valve Doesn't Work and the Boom's Not Enough

"Oil spill" -- it's a dirty noun, and with good reason. For many of us who have been around for more than a few decades, it even triggers some residual trauma. Who can forget the images of dying fish and seabirds washing up on the shores of Prince William Sound, Alaska, courtesy of the Exxon Valdez? Or the ban on fishing that lasted for over 5 months in the fertile Narraganset Bay off of Rhode Island because of a tanker-tug boat collision? Yes, there are many serious consequences to oil contamination in our oceans, and this latest event in the Gulf of Mexico is going to be no exception.

Though the International Tanker Operators Pollution Federation Limited proudly explains how the incidences of oil spills -- regardless of their source -- has significantly declined in the last thirty years (see the graph at right), it doesn't negate the fact that when they do happen, the results aren't pretty. Efforts to stop the leak in the Gulf through the use of robot submarines (closing the well's valve manually) have been unsuccessful, and in the three days since they started trying, the oil slick has moved more than ten miles closer to the shore, threatening wetlands, beaches, and wildlife from Louisiana to Florida. As of Wednesday morning, the slick is 40 miles wide, 80 miles long, and growing by the hour.

The viscosity and density of oil is different than water, and so tends to float on top of it. That is why the early deployment of booms is an important first step in containing spills. Unfortunately, wave action churns crude oil under, creating what looks like "chocolate mousse", and then that oil sinks -- contaminating the delicate ecosystem.

Responses to such spills can take many forms. Boats crews with booms and skimmers can try to contain and mop up the oil before it spreads too far. Planes and helicopters can dump dispersant chemicals into the slick to help the oil break down faster and be less harmful to the ecosystem (think: dropping some Dawn into a sink full of greasy dishes). Pollution containment devices can be constructed at the source, such as a leaking well, to capture the oil. And the oil can be lit on fire, about 95 percent of which is released as carbon dioxide and water into the atmosphere.

While the efforts of the Coast Guard and BP are noble and appreciated -- they are trying a blend of all these techniques -- it appears that they are still weeks away from full containment, and a good three months away from stopping the leak permanently. In the meantime, the oil is expected to reach the Gulf shores as early as this weekend.

Are you using this important news event in your classroom and teaching? We would love to hear how. Share with us and other educators here, or on our Facebook page, how you are talking with students or colleagues about oil spills and cleanups. we would also love to hear about preventative measures folks along the Gulf can take now to protect their shoreline.

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